Agent Foskett Hub
Agent Foskett Hub is GEMXIT’s Microsoft Security Investigation Library — a growing knowledge base spanning KQL, Microsoft Defender XDR, Microsoft Sentinel, Microsoft Entra, Defender for Endpoint, Defender for Cloud, Microsoft Security Copilot, SOC operations, phishing, identity risk, endpoint behaviour and cloud security. The Academy combines structured learning paths with investigation-led lessons, while the SOC Analyst Academy brings KQL, Sentinel, Defender XDR, Entra, endpoint, cloud and Security Copilot skills together in realistic security operations workflows.
About the briefings
Agent Foskett briefings translate real technical observations into clear, practical lessons for organisations operating modern Microsoft environments. They focus on the kinds of issues that often go unnoticed until they become operational, security or governance risks.
What's New
✔ Structured Microsoft Security learning paths • ✔ KQL threat hunting and detection engineering • ✔ SOC Analyst Academy • ✔ Microsoft Security Copilot Academy • ✔ Real-world investigation case files • ✔ Weekly Friday Cyber Briefings.
Agent Foskett Investigates Microsoft Security
Published 1 September 2026 — available now. Available in Kindle, paperback and hardcover editions.
30 real-world investigations using Microsoft Defender XDR, Microsoft Sentinel, KQL and Microsoft Security Copilot. Follow identity, email, endpoint and cloud evidence as Agent Foskett builds timelines, tests theories and asks the question that matters: what do the logs actually prove?
Built from the same investigation-first thinking behind the Agent Foskett Hub, the book brings the stories, evidence, KQL and lessons together into a single practical journey through modern Microsoft security investigation.
Learn KQL
Start with the Academy for a structured path from your first KQL query through Defender XDR hunting, complete identity, endpoint and cloud investigations, and now advanced detection engineering and proactive threat hunting.
Open the AcademyLearn Microsoft Sentinel
Build practical SIEM and SOAR capability through lessons on workspaces, data connectors, analytics rules, incidents, hunting, workbooks, playbooks and automation.
Open Sentinel AcademyMicrosoft Security Copilot
Explore the Security Copilot Academy covering prompts, grounding, plugins, permissions, incident investigation, threat hunting, promptbooks, governance and AI-enabled SOC workflows.
Open Security Copilot AcademySOC Analyst Academy
Bring the specialist Academies together in realistic SOC workflows covering alert triage, evidence gathering, investigation, containment, escalation and defensible analyst decision-making.
Open SOC Analyst AcademyInvestigate Signals
Use the Investigation Library to follow real Microsoft security scenarios across email, identity, endpoint, cloud and session activity.
Search investigationsBuild Capability
Connect the stories, guides and Academy lessons into practical defensive capability for Microsoft 365 and Azure environments.
Discuss your environmentBrowse by topic
Latest investigations
Recent Agent Foskett case files covering social engineering, Defender tampering, OneDrive behaviour, session theft, device lifecycle risk and investigation-led Microsoft security.
- The $3.2 Billion Investor Who Also Had 800 KG of Gold
- The Bulk Fertilizer Order Was Only The Bait
- The Defender Exclusion Was Added 12 Minutes Before the Malware Ran
- The User Didn't Upload the File — OneDrive Did It Automatically
- The Password Was Never Stolen — The Browser Cookie Was
- The Intune Device Was Retired — But It Was Still Accessing Microsoft 365
Friday Cyber Briefings
Agent Foskett also supports GEMXIT’s ongoing Friday Cyber Briefings — practical weekly reflections on Microsoft security, attacker behaviour, governance gaps and the operational lessons hidden inside real-world technology environments.
- Follow GEMXIT on LinkedIn
- Practical Microsoft security thinking, not generic cyber noise
New to Agent Foskett?
Start with the cornerstone investigations that explain how the hub works: follow the signal, question the dashboard, and use KQL to understand what really happened.
- Agent Foskett Academy — Learn KQL From The Beginning
- Microsoft Security Copilot Academy — AI-Assisted Security Investigations
- Microsoft Defender KQL Threat Hunting Guide
- Microsoft Defender KQL Threat Hunting Complete Guide
- SpoofedDomain and EmailEvents Investigation
- MFA Session Hijacking Investigation
Investigation categories
The Agent Foskett Hub is organised around the Microsoft security signals that matter most during real investigations.
How Agent Foskett investigations work
Each investigation is designed to teach a repeatable method, not just tell a one-off story.
- Start with the signal. Identify the email, alert, sign-in, process, URL click or configuration detail that started the investigation.
- Validate the evidence. Use Microsoft Defender XDR, Sentinel, Entra ID and KQL to confirm what really happened.
- Correlate the telemetry. Connect email, identity, endpoint, cloud and user activity into a single investigation path.
- Build the timeline. Put the events in order so the story becomes clear.
- Extract the lesson. Turn the investigation into a practical defensive improvement.
About Jonathan Foskett and Agent Foskett
Agent Foskett is the educational cyber security investigation persona created by Jonathan Foskett, Managing Director of GEMXIT and Microsoft Certified Trainer. The Hub shares practical Microsoft Defender XDR investigations, KQL techniques and Microsoft security lessons for organisations that want to understand what their logs are actually saying.
Why security professionals use the Agent Foskett Hub
The Hub combines structured Academy learning paths, practical Microsoft security investigations, dedicated KQL, Defender XDR, Sentinel, Entra, Defender for Endpoint, Defender for Cloud and Security Copilot content, plus investigation-led Identity Threat Hunting and Advanced Endpoint Investigation modules. It is built for defenders who want clear explanations, realistic evidence chains and useful Microsoft security lessons without the noise.
Why organisations use the Agent Foskett Hub
Most Popular Guides
Microsoft Security Investigation Library
The question was simple:
“Is this malware?”
Security Copilot found no evidence of malware. The response was accurate. The investigation was closed.
But nobody asked about the suspicious sign-in, the new inbox rule, the OAuth consent, the authentication-method change or the unusual SharePoint downloads that followed.
This Agent Foskett investigation explores Microsoft Security Copilot, AI-assisted security investigations, prompt quality, Microsoft Defender XDR, Microsoft Entra ID and why AI can give a completely correct answer while the investigation still reaches the wrong conclusion.
join Revealed The Attacker
The email looked harmless.
The URL click appeared unrelated.
The endpoint showed no obvious malware.
The sign-in looked legitimate.
Every Microsoft Defender XDR table told part of the story. None revealed the full attack.
Then a single KQL
join connected the evidence.
Email activity, URL clicks, endpoint telemetry and identity events became one complete investigation timeline.
This Agent Foskett investigation explores KQL joins, Microsoft Defender XDR, EmailEvents, UrlClickEvents, DeviceProcessEvents and how correlating data across multiple tables uncovers attack paths that individual queries can easily miss.
This Agent Foskett briefing introduces practical KQL threat hunting across Microsoft Defender, Sentinel and Entra ID, showing how simple queries can uncover suspicious sign-ins, email activity, endpoint behaviour and patterns that dashboards may not explain.
This Agent Foskett investigation uses KQL, EmailEvents and AuthenticationDetails to detect spoofed sender domains, DMARC failures, sender mismatch and suspicious delivery outcomes inside Microsoft Defender.
Everything looked legitimate. Then Microsoft Defender reported a Composite Authentication failure.
This Agent Foskett investigation explores Composite Authentication, EmailAuthenticationResults, AuthenticationDetails, email trust decisions and why passing traditional authentication checks does not always mean an email should be trusted.
SPF = Pass.
Everyone assumed the sender was legitimate.
But SPF had authenticated the envelope sender domain—not the visible From domain the user actually trusted.
The visible sender appeared familiar. The sending domain was authorised. The two identities were not the same.
This Agent Foskett investigation explores SPF alignment, SenderFromAddress, SenderMailFromAddress, AuthenticationDetails, EmailEvents, email authentication and how Microsoft Defender XDR helps investigators identify messages that pass SPF for a domain the recipient never expected.
Nobody questioned the message.
Then Microsoft Defender recorded one small detail.
DMARC = Fail.
This Agent Foskett investigation explores DMARC failures, SPF, DKIM, EmailAuthenticationResults, AuthenticationDetails, sender validation, email spoofing and how a single authentication result can become the starting point for a complete Microsoft Defender XDR investigation.
But the real clue wasn't the prize.
It was the Reply-To address.
This Agent Foskett investigation explores Reply-To, From addresses, email headers, sender impersonation, social engineering, Microsoft Defender XDR and how a single header field can expose the true destination attackers want victims to contact.
USD $3.2 billion.
But apparently that wasn't enough.
There were also 800 kg of 24-carat gold bars available for anyone who might be interested.
The supposed CFO represented one company, but the email came from a completely different domain.
Then came the request for a WhatsApp video call, KYC, due diligence and identity verification.
This Agent Foskett investigation explores investment scams, suspicious sender domains, social engineering, EmailEvents, EmailUrlInfo, Microsoft Defender XDR, KQL and how defenders can pivot from an extraordinary claim into the telemetry behind the message.
But the script ran from AppData.
This Agent Foskett investigation explores suspicious script execution, user-writable folders, PowerShell activity, parent-child process relationships, DeviceProcessEvents, DeviceFileEvents, DeviceRegistryEvents and how Microsoft Defender XDR helps investigators follow behaviour rather than trust a filename.
It ran at a predictable time.
Nothing about the task name immediately looked malicious.
Then Agent Foskett stopped looking at the name and followed what the task actually launched.
A trusted Windows component.
PowerShell.
A script inside a user-writable location.
The scheduled task wasn't the conclusion. It was the beginning of the timeline.
This investigation uses DeviceProcessEvents, DeviceFileEvents and DeviceRegistryEvents to trace scheduled-task creation, process execution, PowerShell activity and persistence evidence in Microsoft Defender XDR.
One device.
One detection.
One obvious place to investigate.
But Agent Foskett didn't stop at the alerted endpoint.
He extracted the evidence from the detection and started hunting.
File hashes. Command-line behaviour. Accounts. URLs. Network destinations.
The alert named one device. The evidence found six.
This Agent Foskett investigation uses DeviceProcessEvents, DeviceFileEvents, DeviceNetworkEvents and KQL to expand a Microsoft Defender XDR investigation beyond the endpoint where the original alert fired.
No malware was detected. No malicious file was quarantined. The endpoint appeared clean.
But the browser had launched a Windows utility.
That process launched another process. Then came an outbound network connection.
The scan was clean. The behaviour wasn't.
Agent Foskett followed the process tree.
This Agent Foskett investigation explores Microsoft Defender XDR, DeviceProcessEvents, DeviceNetworkEvents, parent-child process relationships, command-line analysis, living-off-the-land activity and KQL techniques for investigating suspicious endpoint behaviour when antivirus detects nothing.
The filename did not immediately explain why it had appeared on the device.
Then Microsoft Defender XDR revealed something unusual.
Before execution, the same file had appeared under several different names.
The names changed. The hash did not.
This Agent Foskett investigation explores DeviceFileEvents, DeviceProcessEvents, SHA1 correlation, file rename activity, initiating processes, execution timelines and how Microsoft Defender XDR can reconstruct the history of a suspicious file even when its filename keeps changing.
Then, at exactly 2:41AM, Windows created a new Scheduled Task.
That single event quietly restored the attack every time the device restarted.
This Agent Foskett investigation explores Windows Scheduled Tasks, persistence techniques,
schtasks.exe, DeviceProcessEvents, DeviceRegistryEvents,
DeviceEvents and how Microsoft Defender XDR helps investigators uncover attacker persistence hidden inside legitimate Windows automation.
Then, at exactly 8:00 AM, PowerShell launched again.
Microsoft Defender XDR revealed a scheduled task silently re-establishing attacker access every morning. This Agent Foskett investigation explores Windows Scheduled Tasks, persistence techniques, DeviceEvents, DeviceProcessEvents, DeviceRegistryEvents and how investigators uncover malicious automation hidden inside legitimate Windows task scheduling.
The name looked legitimate. The executable looked legitimate. It even ran as SYSTEM.
Nothing immediately screamed attacker persistence.
Then Agent Foskett asked a different question:
Who actually created it?
The answer changed the investigation.
This Agent Foskett investigation follows scheduled task creation, creator identity,
schtasks.exe,
parent processes, account context and Microsoft Defender XDR
telemetry to uncover suspicious activity hiding behind
legitimate-looking Windows automation.
They acted immediately.
The process was stopped. The malicious file was deleted. The machine was cleaned up.
Problem solved.
Except the SOC had not finished investigating.
By the time Agent Foskett arrived, some of the original evidence was already gone.
The question was no longer simply:
“Is the device clean?”
It became:
“What happened before the cleanup?”
This Agent Foskett investigation follows DeviceProcessEvents, DeviceFileEvents, process history, administrator activity and the remediation timeline to reconstruct what happened before the scene changed.
Then Microsoft Defender XDR revealed that PowerShell had quietly downloaded a file from the Internet.
This Agent Foskett investigation explores suspicious PowerShell downloads, Invoke-WebRequest, DownloadString, DeviceProcessEvents, DeviceNetworkEvents, DeviceFileEvents and how defenders investigate living-off-the-land activity by following behaviour instead of relying on alerts.
No
http.
No https.
No obvious download URL.
It looked like PowerShell had never contacted the Internet.
But the network telemetry told a different story.
This Agent Foskett investigation explores DeviceProcessEvents, DeviceNetworkEvents, PowerShell execution, process correlation, network connections and how KQL can uncover activity that was never visible in the original command line.
mshta.exe.
The binary looked suspicious.
But the investigation showed the executable was only one step in a much larger attack chain. The real evidence came from the parent process, the child processes and the timeline that connected them.
This Agent Foskett investigation explores Living Off The Land binaries (LOLBins), DeviceProcessEvents, parent-child process relationships, PowerShell execution, DeviceNetworkEvents and how defenders use KQL to reconstruct the complete attack path.
Nothing obvious happened when the USB drive was inserted. Windows stayed quiet. No alerts appeared.
Minutes later, PowerShell started. A scheduled task appeared. The investigation had only just begun.
This Agent Foskett investigation explores removable media attacks, DeviceEvents, DeviceProcessEvents, DeviceRegistryEvents, persistence, scheduled tasks, PowerShell activity and how Microsoft Defender XDR helps investigators reconstruct everything that happened after an unknown USB device was connected.
The message claimed a package plan had been purchased, an order had been processed and payment had already been taken.
Everything was designed to trigger panic.
This Agent Foskett investigation explores fake payment receipts, undeliverable email scams, Microsoft impersonation, social engineering tactics and how attackers exploit urgency to convince users to call fraudulent support numbers or interact with malicious links.
Then the message claimed an Amazon Gift Card payment had already been processed and provided a phone number for "refund enquiries."
This Agent Foskett investigation explores invoice platform abuse, refund scams, trusted SaaS services, EmailEvents, AuthenticationDetails, social engineering and why legitimate email infrastructure can still deliver malicious messages.
By the time investigators looked for it, the message had disappeared.
No inbox. No deleted items. No obvious evidence.
Yet Microsoft Defender already knew exactly what had happened.
This Agent Foskett investigation explores DeliveryAction, DeliveryLocation, ThreatTypes, Zero-hour Auto Purge (ZAP), quarantine actions and how defenders can reconstruct the lifecycle of a malicious email even after the message has been removed.
But one detail changed everything.
The visible link said USPS. The destination pointed somewhere completely different.
This Agent Foskett investigation explores phishing emails, deceptive hyperlinks, EmailUrlInfo, UrlClickEvents, sender impersonation, Microsoft Defender XDR and how attackers reuse legitimate HTML templates to hide malicious links inside convincing emails.
But the user insisted it never appeared in the inbox.
No obvious alert. No visible message. No simple answer.
This Agent Foskett investigation explores DeliveryAction, DeliveryLocation, mailbox placement, quarantine outcomes, junk email routing and why delivered does not always mean the user actually saw the message.
Then another message appeared.
Everyone assumed Microsoft 365 had ignored the block.
Until the Internet headers revealed the truth.
This Agent Foskett investigation explores Exchange Online Protection, Internet headers, High Confidence Spam, Junk Email delivery, anti-spam policies, Microsoft Defender for Office 365 and why blocked senders do not always disappear completely from user mailboxes.
But nobody had sent it.
The Internet headers revealed an automated SMTP bounce, a forged sender address and a classic backscatter spam campaign.
This Agent Foskett investigation explores SMTP delivery failures, Mailer-Daemon messages, Exim mail servers, forged sender addresses, backscatter spam and how email headers reveal emails that were never actually sent.
But one detail didn't fit. The sender domain didn't match the company requesting the quote.
This Agent Foskett investigation explores procurement scams, business email fraud, supplier impersonation, social engineering and how attackers use professional purchasing requests to begin conversations that can later lead to financial fraud or business email compromise.
GEMXIT had apparently been selected and approved as one of Australia's best businesses.
There was only one small problem.
I couldn't remember entering anything.
This Agent Foskett investigation explores unsolicited business recognition emails, social engineering, authority and trust signals, commercial persuasion, EmailEvents, EmailUrlInfo, Microsoft Defender XDR and why an unexpected email does not have to be malicious before it deserves investigation.
The sender claimed they had come across GEMXIT's website and noticed an opportunity to generate more enquiries.
There was only one problem.
Nothing in the email suggested they had actually looked at the website at all.
This Agent Foskett investigation explores unsolicited sales emails, cold outreach, commercial persuasion, social engineering, EmailEvents, sender context, Microsoft Defender XDR and why a suspicious or unwanted email should not automatically be classified as phishing without evidence to support that conclusion.
The device appeared protected.
Then malware executed from a location where Agent Foskett expected Defender to intervene.
So why didn't it?
Working backwards through the endpoint evidence revealed something far more interesting than the malware itself.
Just 12 minutes before execution, a Microsoft Defender exclusion had been added.
This Agent Foskett investigation explores Defender exclusions, security control tampering, DeviceRegistryEvents, DeviceProcessEvents, DeviceFileEvents, KQL and why the absence of an expected alert can become evidence of its own.
The visible From address appeared trustworthy. But the envelope sender told a different story.
This Agent Foskett investigation explains how defenders compare SenderFromAddress and SenderMailFromAddress in Microsoft Defender XDR to uncover spoofing, impersonation, mismatched sender identity and suspicious email authentication behaviour.
This Agent Foskett lesson explains how startswith and endswith help narrow evidence during Microsoft Defender XDR and Sentinel investigations.
Everything looked legitimate.
But the user approved a malicious OAuth application and granted access to the mailbox through Microsoft 365 permissions. This Agent Foskett investigation explores OAuth consent phishing, malicious app permissions, offline access, mailbox visibility and why successful MFA does not always mean the session is safe.
Then the user clicked Accept.
That single approval granted an application permission inside Microsoft 365. No malware was required. No password was needed.
This Agent Foskett investigation explores OAuth consent abuse, application permissions, service principals, Microsoft Entra ID and how attackers can gain access through trusted application workflows.
Then the permissions were reviewed.
A service principal had Global Administrator-level access.
This Agent Foskett investigation explores Microsoft Entra ID, service principals, enterprise applications, privileged permissions and how application identities can quietly become one of the most powerful attack paths inside a Microsoft 365 tenant.
But when Agent Foskett checked the app registration, there was no client secret.
No password-style credential.
Nothing obvious explaining the successful authentication.
Except the service principal was clearly active.
No client secret did not mean no credential.
Agent Foskett traced the workload identity, reviewed the service principal, examined its workload sign-ins and inspected the application's credentials.
The missing piece was a certificate-based key credential.
This investigation uses AADServicePrincipalSignInLogs, AuditLogs, Microsoft Graph and KQL to reconstruct how an application was authenticating without a client secret.
Its name looked familiar.
Its service principal had existed for months.
But its effective access was more powerful than anyone expected.
Microsoft Graph application permissions were assigned to it — and nobody remembered approving them.
Agent Foskett followed the service principal.
The app role assignment.
The resource service principal.
The permission ID.
The audit event.
The identity that initiated the change.
Then came the next question.
Having the permission was one thing — had the application actually used it?
Agent Foskett followed the workload sign-ins and downstream evidence to separate authorization from actual activity.
This investigation uses Microsoft Entra ID, AuditLogs, AADServicePrincipalSignInLogs, Microsoft Graph and KQL to reconstruct how an enterprise application gained powerful access.
No impossible travel.
No MFA prompt.
No interactive session.
Instead, one application identity had become extraordinarily busy.
Before most of the SOC had started work, one service principal had made more than 6,000 Microsoft Graph requests.
Agent Foskett followed the workload identity.
The service principal.
The authentication activity.
The source IPs.
The Graph endpoints.
The request methods.
The permissions.
Then the behaviour started to look different.
The volume was unusual.
The endpoints had changed.
Write operations appeared where the workload normally performed reads.
But 6,000 requests alone did not prove compromise.
Was this expected automation — or had a workload identity become the attacker?
This investigation uses Microsoft Entra ID, AADServicePrincipalSignInLogs, MicrosoftGraphActivityLogs and KQL to investigate abnormal service-principal behaviour and determine what the application actually did.
Then the authentication methods were reviewed.
A new MFA method had been added at 3:14AM. The user was asleep.
This Agent Foskett investigation explores suspicious MFA registration, Microsoft Entra ID AuditLogs, authentication method changes, account takeover persistence and why password resets alone do not always remove attacker access.
They hadn't changed it.
They hadn't requested a reset.
They hadn't contacted the help desk.
But Microsoft Entra ID showed that the credential had changed.
So who changed the password?
Agent Foskett followed the Entra audit trail.
AuditLogs revealed the password operation, the affected identity and the account responsible for initiating it.
But identifying the reset wasn't enough.
What happened to the account after the password changed?
Agent Foskett pivoted into SigninLogs, identified the first authentication after the reset and reconstructed the wider identity timeline.
This investigation uses Microsoft Entra ID, AuditLogs, SigninLogs and KQL to investigate an unexpected password reset and determine who actually initiated it.
Today they could.
No application role had been assigned directly to the account.
No one remembered approving new access.
But one thing had changed.
The user was now a member of the group that granted it.
Agent Foskett followed the Microsoft Entra audit trail.
The membership event.
The target group.
The initiator.
The effective access.
The subsequent sign-ins.
Then came the important question:
Who added the user — and what happened after the access changed?
This investigation uses Microsoft Entra ID, AuditLogs, SigninLogs and KQL to investigate an unexpected group membership change and reconstruct the resulting access window.
No recent workload sign-ins.
No obvious reason for it to suddenly become active.
Then privileged role activity appeared in the Microsoft Entra audit trail.
A non-human identity was now part of the investigation.
Agent Foskett followed the identity evidence.
The privileged role event.
The initiator.
The target.
The service principal.
The workload sign-ins.
The source IP addresses.
The resources accessed.
But there was an important distinction to make.
Did the service principal change the role — or was it the identity receiving the privilege?
Agent Foskett separated the actor from the target and reconstructed the workload identity timeline.
This investigation uses Microsoft Entra ID, AuditLogs, AADServicePrincipalSignInLogs and KQL to investigate dormant workload identity activity around a privileged role change.
That should have been unusual by design.
There was no tenant lockout.
No outage requiring emergency administration.
No scheduled validation exercise.
So why had the break-glass account been used?
Agent Foskett followed the identity evidence.
The successful sign-in.
The source IP.
The application.
The target resource.
The authentication context.
The account's previous activity.
Then he followed the privileged identity into the audit trail.
What happened after the emergency account authenticated?
Agent Foskett checked directory changes, account modifications and the resources accessed after the sign-in.
This investigation uses Microsoft Entra ID, SigninLogs, AuditLogs and KQL to investigate unexpected use of an emergency access account and reconstruct the privileged activity timeline.
Nothing about that single event proved the account had been compromised.
Then, eleven minutes later, a new authentication method was registered.
That changed the investigation.
This Agent Foskett investigation explores suspicious sign-ins, MFA registration, Microsoft Entra ID audit activity, authentication-method changes, account takeover persistence and how investigators correlate separate identity events into a single compromise timeline.
It was not a Global Administrator.
Everything appeared normal.
But the audit trail showed something the current role assignment could not.
For seventeen minutes, the account had held one of the most powerful roles in Microsoft Entra ID.
This Agent Foskett investigation explores Microsoft Entra Privileged Identity Management, temporary Global Administrator activation, AuditLogs, privileged role changes, KQL and why investigators must reconstruct what permissions an identity had during the incident — not simply what permissions it has now.
It wasn't one of the recognised administrator accounts.
Yet it held one of the most powerful roles in the tenant.
Global Administrator.
The team searched for the obvious answer:
Who created the account?
But Agent Foskett had a better question:
Who gave this identity privilege?
This Agent Foskett investigation explores Microsoft Entra ID, Global Administrator, AuditLogs, RoleManagement, Privileged Identity Management, role assignments, administrative activity and KQL techniques for reconstructing how unexpected privilege appeared inside a Microsoft 365 tenant.
The user wasn't there.
No membership.
No obvious entitlement.
No reason they should still have access.
Except they did.
The group membership was correct. The assumption about the permission path wasn't.
Agent Foskett worked backwards from the resource, tracing direct assignments, alternate groups, supported nested-group relationships and Microsoft 365 permission evidence.
This investigation uses Microsoft Entra audit evidence, AuditLogs, OfficeActivity and KQL to reconstruct how effective access can remain even when the expected security group says otherwise.
No permanent Global Administrator assignment.
No standing privileged role.
Nothing in the current role list explained the administrative action.
But the audit trail showed something the current-state view couldn't.
For a limited window, the account had been privileged.
Microsoft Entra Privileged Identity Management had activated the role.
Agent Foskett reconstructed the PIM activation, defined the privilege window, examined the administrative actions performed while the role was active and correlated the elevation with sign-in evidence.
This investigation uses AuditLogs, SigninLogs and KQL to investigate temporary privileged access in Microsoft Entra ID.
MFA was satisfied. Conditional Access reported Success.
Everything appeared to have worked exactly as designed.
But Agent Foskett had a different question:
What exactly had succeeded?
This investigation explores Microsoft Entra Conditional Access, sign-in logs, authentication details, device context, report-only policies, session evidence and how KQL helps investigators understand what happened before and after a successful authentication.
It was enrolled. It was compliant. Conditional Access allowed access.
Everything appeared trustworthy.
But the activity that followed did not match the device everyone thought they were investigating.
This Agent Foskett investigation explores Microsoft Entra ID, Conditional Access, device compliance, session context, token replay, DeviceInfo, DeviceNetworkEvents and how KQL helps investigators determine whether a trusted device really explains the activity that followed.
Everything looked normal.
Then Entra ID flagged the sign-in as High Risk.
The login was successful. The investigation was only beginning.
This Agent Foskett investigation explores Microsoft Entra ID Identity Protection, risky sign-ins, SigninLogs, impossible travel indicators, unfamiliar locations, Conditional Access decisions and why successful authentication does not automatically mean a session is trustworthy.
Everything looked normal.
Then SharePoint downloads increased. New authentication methods appeared. Enterprise applications were granted consent. The investigation had only just begun.
This Agent Foskett investigation explores Microsoft Entra Sign-in Logs, Authentication Details, Conditional Access, Risky Sign-ins, Audit Logs and why successful authentication should mark the beginning of an investigation—not the end.
The password was correct. MFA succeeded. The authentication came from the expected device.
Then the same identity began accessing Microsoft 365 from Singapore.
The password had not necessarily been stolen.
Agent Foskett had a different question:
What if the attacker didn't need the password anymore?
This Agent Foskett investigation explores Microsoft Entra ID, session tokens, interactive and non-interactive sign-ins, IP address correlation, SigninLogs, AADNonInteractiveUserSignInLogs, Microsoft Defender XDR and KQL techniques for investigating suspected token theft.
It signed in successfully.
It used familiar applications.
Nothing looked obviously destructive.
Compared with the user's own recent history, very little looked unusual.
Then Agent Foskett changed the comparison.
What if the account was compared with its peers instead?
BehaviorAnalytics contained another clue.
The action was not necessarily new for the user.
But it was uncommon among the user's peers.
History said: seen before.
Peer context said: still unusual here.
Agent Foskett followed the behavioural evidence.
The UEBA event.
The ActivityInsights.
The peer relationships.
The identity context.
The underlying sign-ins.
Then came the important question.
Was the behaviour malicious — or did the user's role legitimately differ from their peers?
This investigation uses Microsoft Sentinel UEBA, BehaviorAnalytics, ActivityInsights, UserPeerAnalytics, IdentityInfo and KQL to investigate behaviour that only became suspicious when the baseline changed.
A user appeared to sign in from Melbourne and then Singapore only minutes later. No commercial flight could explain the journey.
The risk score increased. The investigation suggested account compromise.
Then the device details, IP addresses and session timeline told a different story.
This Agent Foskett investigation explores Microsoft Entra ID Impossible Travel alerts, VPN exit nodes, risky sign-ins, device continuity, identity telemetry and why unusual location data does not always mean the user account was compromised.
This Agent Foskett investigation explores impossible travel sign-ins, suspicious location changes, risky authentication events and why identity telemetry must be reviewed before assuming the account is safe or compromised.
No malware alert fired. No suspicious attachment was opened. No impossible travel alert immediately explained what happened.
But the phone kept buzzing. Again and again.
Eventually, the user pressed Approve. This Agent Foskett investigation explores MFA fatigue attacks, push bombing, repeated authentication prompts, suspicious sign-in behaviour and why a normal-looking MFA prompt can still be part of an active compromise.
The user simply scanned a QR code. The Microsoft 365 login page looked familiar. The authentication flow looked legitimate.
But the QR code redirected the user into a credential harvesting and session theft workflow designed to move the attack away from the protected corporate device and onto a trusted mobile phone.
This Agent Foskett investigation explores QR phishing attacks, mobile authentication abuse, suspicious sign-ins, token theft, Microsoft Entra ID investigations and how attackers increasingly abuse trusted mobile workflows inside Microsoft 365 environments.
No impossible travel alert. No failed login attempts. Nothing appeared obviously malicious.
But the attacker never needed to bypass MFA. They inherited the authenticated session instead. This Agent Foskett investigation explores session hijacking, token theft, browser cookie abuse and how attackers operate inside trusted Microsoft 365 sessions after authentication has already succeeded.
Their password had not been changed.
There was no obvious password spray.
Yet somebody was accessing Microsoft 365 from a network the user had never used.
The obvious assumption was: the attacker must have stolen the password.
Agent Foskett followed the session evidence instead.
The attacker may never have needed the password at all. The authenticated browser session was the real target.
This Agent Foskett investigation explores session hijacking, browser cookie theft, token replay, Microsoft Defender XDR, CloudAppEvents, IP addresses, user agents and KQL techniques for investigating suspicious Microsoft 365 session activity.
The security controls worked exactly as designed.
Then the attacker logged in.
The investigation revealed that authentication had succeeded, but the identity behind the session was not the person everyone expected.
This Agent Foskett investigation explores Microsoft Entra ID sign-in telemetry, successful MFA events, risky authentication patterns, session trust, identity compromise and why passing MFA does not always mean the investigation is over.
But the attacker was already inside the trusted device. This Agent Foskett investigation explores how modern attackers abuse legitimate corporate endpoints, session tokens, browser cookies and inherited trust inside Microsoft environments.
The user was absolutely certain.
No password sent in an email. No credentials entered into a suspicious website. No MFA code read over the phone.
But somebody had still been operating their computer.
Then Agent Foskett asked one more question:
“Did anybody ask you to share your screen?”
The attacker had impersonated IT support and persuaded the user to open Quick Assist, share their screen and approve remote control.
This investigation follows Quick Assist activity, endpoint processes, network connections, remote-control evidence and Microsoft Defender XDR telemetry to reconstruct what happened after the user granted access.
It was supposed to be leaving management.
Then the Microsoft Entra sign-in logs showed something awkward.
The same device was still appearing in Microsoft 365 activity after the retire action.
The obvious conclusion was that Intune had failed.
Agent Foskett followed the timestamps and found a much more important question:
When did the retire action actually reach the device?
This Agent Foskett investigation explores Microsoft Intune, Microsoft Entra sign-in logs, device identity, Conditional Access, retirement timing and how KQL can reconstruct what really happened.
Everything appeared secure.
Then the Conditional Access policy was reviewed.
It was still in Report-only mode.
Sign-ins were being evaluated. The logs showed what the policy would have done. But no access decision was actually being enforced.
This Agent Foskett investigation explores Microsoft Entra Conditional Access, Report-only mode, policy assignments, exclusions, Sign-in Logs, the What If tool and why a configured security policy does not protect anything until enforcement is enabled.
But after a suspicious sign-in, a new inbox rule appeared. Messages were quietly moved out of sight before anyone knew to investigate.
This Agent Foskett investigation explores hidden mailbox rules, CloudAppEvents, EmailEvents, UrlClickEvents and KQL to uncover post-compromise activity designed to conceal suspicious email from users and defenders.
But at 2:13AM, a new inbox rule quietly appeared inside the mailbox. The rule forwarded messages externally, moved replies into hidden folders and reduced the chance the user would notice suspicious activity.
This Agent Foskett investigation explores hidden mailbox persistence, suspicious forwarding behaviour and post-authentication compromise activity across Microsoft 365 environments.
But hidden inside Microsoft Defender XDR telemetry were subtle behavioural signals: unusual sign-ins, suspicious SharePoint activity, persistent sessions and authentication patterns that did not match normal business behaviour.
This Agent Foskett investigation explores why modern security teams must move beyond dashboards and learn how to ask the data better questions.
Within hours, two servers, fifteen workstations and the on-site backups were encrypted.
Then the ransom note appeared.
The attackers believed recovery was impossible because every system they could see had already been destroyed.
This Agent Foskett investigation explores ransomware recovery, encrypted backup systems, disaster recovery planning, business continuity and the cloud backup that ultimately saved the business.
“Did antivirus detect anything?”
But modern attacks rarely look like traditional malware anymore. The dashboard may stay green while attackers operate quietly through trusted sessions, successful MFA prompts, OAuth abuse, browser token theft and suspicious cloud activity.
This Agent Foskett investigation explores why Microsoft Defender XDR, Sentinel, Entra ID telemetry and KQL threat hunting have become critical for investigating the hidden signals modern antivirus often misses.
Then the download activity was reviewed.
More than 4GB of company data had been downloaded shortly before the employee resigned.
This Agent Foskett investigation explores SharePoint and OneDrive download activity, CloudAppEvents, behavioural baselining, data exfiltration, insider risk and how Microsoft Defender XDR can reveal unusual cloud behaviour even when the identity itself appears completely legitimate.
There wasn't one.
No 4GB transfer. No suspicious archive. No obvious mass-download event.
Yet sensitive company files had still been exposed.
The attacker hadn't taken the data.
They had changed who could access it.
This Agent Foskett investigation explores SharePoint, OneDrive, external sharing, CloudAppEvents, Microsoft Defender XDR, cloud audit activity and how KQL can uncover data exposure that never looks like traditional file exfiltration.
Nothing unusual appeared.
No 4GB browser download. No obvious file-transfer spike. No malware alert.
But thousands of company files had still arrived on the user's device.
The files were never downloaded one by one. OneDrive had synchronised the library.
This Agent Foskett investigation explores OneDrive and SharePoint synchronisation, CloudAppEvents, endpoint telemetry, data movement and why investigators must search for outcomes rather than only the actions they expect.
The obvious explanation?
Thirty-seven downloads.
Except the evidence showed only one.
The file had been downloaded to one endpoint and then propagated internally across the network.
Agent Foskett followed the file hash, device activity, initiating processes, network connections and SMB evidence to reconstruct how one copy became 37.
The important question was no longer:
“Who downloaded the file?”
It was:
“How did the other 36 devices get it?”
The audit trail showed cloud activity.
There was only one problem.
The user insisted they had never uploaded it.
Agent Foskett followed the timeline back to the endpoint and found the missing piece.
The file had been created locally inside a synchronised folder, and OneDrive had moved it into the cloud automatically.
This Agent Foskett investigation explores OneDrive, cloud synchronisation, CloudAppEvents, DeviceFileEvents, DeviceProcessEvents, endpoint-to-cloud correlation and how KQL can distinguish a deliberate upload from an automatic synchronisation event.
Then the permissions were checked.
The file was accessible to everyone. This Agent Foskett investigation explores SharePoint sharing links, OneDrive permissions, anonymous access, external collaboration and how sensitive information can become exposed without a single attacker.
The expected users had access.
The expected groups had access.
Nothing in the visible membership suggested public exposure.
But the audit trail contained another permission path.
Someone had created an anonymous sharing link.
Agent Foskett reconstructed the sharing event, identified the affected content, investigated who created the link and defined the potential exposure window.
Then came the important question:
Was the link merely created — or was the content actually accessed?
This investigation uses Microsoft 365 audit evidence, OfficeActivity and KQL to investigate anonymous SharePoint sharing and distinguish potential exposure from confirmed access.
A user had handled a document containing sensitive information.
The business explanation sounded plausible.
It would have been easy to classify the alert as noise and move on.
Agent Foskett did something else.
He followed the file.
The SharePoint activity.
The download.
The user.
The device.
The processes that handled the file.
The surrounding network connections.
Then the timeline started to change.
The DLP event was not the first event.
It was one point in a much longer file history.
Agent Foskett correlated Microsoft 365 audit evidence with endpoint telemetry and followed the document beyond the original alert.
Then came the real question.
Was the complete data-handling path actually authorised?
This investigation uses Microsoft Purview DLP, OfficeActivity, DeviceFileEvents, DeviceNetworkEvents and KQL to reconstruct the movement of sensitive information.
But the investigation showed something uncomfortable: active sessions were still alive, authentication tokens still existed, and access continued quietly in the background.
This Agent Foskett investigation explores incomplete offboarding, persistent Microsoft 365 sessions, refresh token survival, remembered devices and why disabling an account does not always terminate access immediately.
Everyone assumed the attacker had been locked out.
Then activity continued.
The password was no longer the important part of the investigation. A session already existed, and the evidence showed why disabling an account should never be treated as proof that containment is complete.
This Agent Foskett investigation explores Microsoft Entra ID, refresh tokens, persistent sessions, interactive and non-interactive sign-ins, session revocation, Conditional Access and how investigators verify that access has actually stopped after an account is disabled.
No impossible travel alert. No malware detection. No obvious compromise warning.
But at 3:12AM, the user was quietly added to a privileged Microsoft Entra ID role. Global Administrator.
This Agent Foskett investigation explores privilege escalation, suspicious role assignments, PIM abuse, overnight administrative access and how attackers quietly move from user access to tenant control inside Microsoft 365.
Everything looked like it was protected.
But the policy was still in Report-Only mode. It evaluated the sign-in, recorded the result, and showed what would have happened.
It did not block anything.
This Agent Foskett investigation explores Conditional Access policies, report-only evaluation, MFA enforcement gaps, sign-in logs and the dangerous difference between a control that exists and a control that is actually enforced.
Yet during investigation, operational exposure still existed beneath apparently compliant Microsoft environments.
This Agent Foskett briefing explores how exclusions, configuration drift, incomplete telemetry and overlooked assumptions quietly survive inside environments that technically appear secure.
The SOC searched Microsoft Sentinel.
Nothing.
No matching security events. No useful timeline. No detection.
The obvious conclusion?
Nothing happened.
Agent Foskett asked a more important question:
“Were we actually collecting the evidence?”
The investigation followed Windows Security Events, SecurityEvent, WindowsEvent, collection coverage, data ingestion and Microsoft Sentinel configuration.
The detection rule had not missed the telemetry.
The telemetry had never arrived.
Configured.
Connected.
No obvious warning demanded attention.
But an analyst noticed something strange.
The newest security events were hours old.
The connector still existed.
The workspace still worked.
The queries still ran.
Only the evidence had stopped arriving.
Agent Foskett stopped looking at the connector's appearance and started measuring the data itself.
The last event time.
The last ingestion time.
The ingestion delay.
The normal event cadence.
The SentinelHealth evidence.
Then came the bigger question.
What could the SOC not see while the telemetry was missing?
The collection problem had become something larger.
A detection coverage gap.
This investigation uses Microsoft Sentinel, SentinelHealth, OfficeActivity, ingestion_time() and KQL to identify stale security telemetry, distinguish delayed ingestion from stopped collection and verify that visibility has actually returned.
At first, that looked like good news.
But the source telemetry was still arriving.
The KQL still returned suspicious activity.
The attacks hadn't stopped.
The detection had.
Agent Foskett checked the Microsoft Sentinel analytics rule.
It had been disabled.
So the investigation changed direction.
When was the rule changed?
Who changed it?
Was the change approved?
And had the same identity modified anything else?
Agent Foskett followed the management trail through SentinelAudit and AzureActivity.
Then came the most important question.
What happened while the SOC was blind?
The original detection logic was run across the gap to find activity that should have generated alerts.
This investigation uses Microsoft Sentinel, SentinelAudit, AzureActivity and KQL to investigate analytics-rule changes and reconstruct the resulting detection gap.
Agent Foskett searched seven days of evidence.
The suspicious activity appeared immediately.
The event matched.
The entities were there.
The evidence was clear.
There was only one problem.
The same activity should have triggered a Sentinel analytics rule.
But no alert had fired.
No incident had been created.
Agent Foskett compared more than the KQL.
The query frequency.
The lookup period.
The event timestamp.
The ingestion time.
The rule configuration.
The alert evidence.
The rule health.
Then the important distinction became clear.
Finding an event now does not prove the rule could see it then.
A historical hunt and a scheduled detection may use similar KQL.
But they do not necessarily execute under the same conditions.
This investigation uses Microsoft Sentinel, DeviceProcessEvents, SecurityAlert, SentinelHealth, ingestion_time() and KQL to investigate why hunting found activity that scheduled detection missed.
A privileged account.
An unusual location.
An unfamiliar source IP.
But the expected Sentinel alert never appeared.
Why?
The IP matched an entry in the organisation's trusted-IP watchlist.
Agent Foskett followed the exception.
The watchlist entry.
The SearchKey.
The business owner.
The original purpose.
The review history.
Then the assumption started to fall apart.
The trusted entry referred to an old connection that was no longer being used.
The detection was not broken.
The assumption feeding the detection was stale.
Agent Foskett removed the trust assumption and hunted the IP directly across the retained telemetry.
Then came the bigger question.
What happened while Sentinel was treating the IP as trusted?
This investigation uses Microsoft Sentinel, watchlists, _GetWatchlist(), SearchKey, SigninLogs and KQL to investigate stale detection exceptions and reconstruct the resulting exposure window.
Three alerts.
One user.
One device.
A tidy sequence of suspicious activity.
But Agent Foskett noticed something strange.
The raw evidence showed suspicious activity before the incident's first alert.
So where was the alert that explained it?
Agent Foskett expanded the investigation.
The incident AlertIds.
The SecurityAlert records.
The shared user.
The shared device.
The wider alert history.
Then he found it.
A fourth alert.
It involved the same investigation context.
It happened earlier.
And it was not part of the incident being investigated.
The fourth alert changed the beginning of the timeline.
Then came the important question.
Was it part of another incident — and why had the evidence been separated?
This investigation uses Microsoft Sentinel, SecurityIncident, SecurityAlert, AlertIds, SystemAlertId and KQL to hunt beyond the incident boundary and reconstruct the wider attack timeline.
Initial access.
Execution.
Persistence.
Response.
The evidence had been documented.
Then two days later, more logs appeared.
They were not new attacker activity.
They were old events arriving late.
Agent Foskett compared two different clocks.
When did the activity occur?
And when did the evidence become available?
Using event timestamps and ingestion_time(), the delay became visible.
Some records had arrived roughly two days after the activity they described.
Then the timeline changed.
The attack had started earlier than the original evidence showed.
The late events were not added to the end of the investigation.
Agent Foskett placed them where they actually belonged.
The incident timeline was rebuilt.
The conclusions were revised.
And another investigation began.
Why had the telemetry arrived so late?
This investigation uses DeviceProcessEvents, ingestion_time(), SentinelHealth and KQL to investigate delayed telemetry and reconstruct the real attack timeline.
No active incidents.
No urgent alerts.
No suspicious activity.
Everything appeared perfectly normal.
Then a new threat intelligence report arrived.
Several suspicious IP addresses had been linked to known malicious infrastructure.
Agent Foskett had a question.
Had anyone checked whether those addresses had already appeared in the organisation's logs?
The investigation moved beyond the alert queue.
Microsoft Sentinel.
Historical network connections.
Microsoft Entra sign-in activity.
Threat intelligence indicators.
"Interesting," Agent Foskett muttered.
"The dashboard says everything is fine."
He opened another KQL query.
"Let's see whether the evidence agrees."
Using Microsoft Sentinel and KQL, this investigation demonstrates how retrospective threat hunting can identify suspicious historical activity that existing security alerts may have missed.
Correct sender.
Correct subject.
Correct conversation history.
Even the invoice looked familiar.
There was just one small problem.
The bank account details had changed.
Agent Foskett began investigating the Microsoft 365 mailbox.
Had the sender's account been compromised?
Had someone accessed the email conversation?
Were suspicious inbox rules hiding messages?
And where had the payment instructions actually originated?
"Interesting," Agent Foskett muttered.
"The email is genuine. Unfortunately, so is the fraud attempt."
Using Microsoft Defender XDR, Exchange Online audit evidence, Microsoft Entra sign-in logs and KQL, this investigation follows the evidence behind a suspected business email compromise.
No errors. No warnings. Everything was green.
The infrastructure team was pleased.
Unfortunately, the deployment had also introduced a Network Security Group rule allowing inbound access from the internet.
The deployment had succeeded. The security configuration hadn't.
Agent Foskett began investigating the Azure Activity Logs, deployment history, NSG rules and resource configurations.
Who made the change?
Which deployment introduced the rule?
What resources were affected?
And was anything actually exposed?
"Apparently," Agent Foskett muttered, "Azure successfully deployed exactly what we asked for."
"Unfortunately, nobody asked whether it was a good idea."
Using Azure Activity Logs, Azure Resource Graph and KQL, this investigation follows the deployment evidence to identify an overly permissive network rule and establish its potential security impact.
"Who is this person?"
An external guest account had appeared in Microsoft Entra ID.
Nothing unusual about that. Organisations invite guests all the time.
Except this guest had access to confidential Finance files.
And nobody seemed to know who had invited them.
Agent Foskett opened the audit logs.
The investigation began with a simple question.
Who created the invitation?
Who granted the permissions?
What files could the guest access?
And had any documents actually been opened?
"I don't mind visitors," Agent Foskett muttered.
"But I'd prefer they didn't have a key to the Finance department."
An invitation is not the same thing as authorisation.
Using Microsoft Entra ID, Microsoft Purview audit logs, SharePoint activity and KQL, this investigation follows the guest account, its permissions and the available access evidence.
No suspicious executable.
No obvious malicious download.
No dramatic security alert.
Just a workstation resolving a hostname.
Except the hostname was unusually long.
Agent Foskett examined the DNS activity.
One query became ten.
Ten became hundreds.
Each request contained a different encoded-looking subdomain.
"That's a lot of enthusiasm for a hostname," Agent Foskett muttered.
The destination domain was consistent.
The subdomains kept changing.
And when the suspicious labels were decoded, the investigation took a very different turn.
DNS was not simply resolving hostnames. It was being used to carry information.
Using Microsoft Defender for Endpoint, Microsoft Sentinel and KQL, this investigation explores DNS tunnelling, encoded subdomains, suspicious query patterns and process-level evidence.
DNS resolved correctly.
The application connected through the private IP address.
Network connectivity tests passed.
Everything appeared secure.
Except the Azure Storage service was still accessible through its public endpoint.
Agent Foskett opened the investigation.
Was the private endpoint misconfigured?
Had public network access been disabled?
Were storage firewall rules allowing unexpected connections?
And could an attacker reach the service without using the private network?
Using Azure Activity Logs, Azure Storage diagnostic logs, Azure networking configuration and KQL, the investigation examines how a correctly functioning private endpoint can coexist with an exposed public endpoint.
Private connectivity does not automatically mean public access has been disabled.
It retrieved information.
Processed the content.
Followed the instructions.
And completed the requested task.
Everything appeared normal.
Except the instructions hadn't come from the authorised user.
Agent Foskett opened the investigation.
Where had the malicious instructions originated?
Had an attacker manipulated retrieved content?
Did the AI agent trust an untrusted data source?
And had any tools or sensitive information been exposed?
Using AI interaction logs, tool execution records, Microsoft security telemetry and KQL, the investigation explores how prompt injection can redirect an otherwise legitimate AI workflow.
An AI agent following instructions does not mean those instructions were trustworthy.
Nobody had deleted it.
No suspicious download was identified.
The original file remained exactly where it belonged.
Everything appeared secure.
Until sensitive information from the document appeared somewhere it shouldn't.
Agent Foskett opened the investigation.
Who accessed the document?
Was sensitive content copied or shared?
Did Microsoft Purview detect a policy violation?
And what evidence could establish how the information was exposed?
Using SharePoint Online, Microsoft Purview DLP, Microsoft 365 audit events, endpoint telemetry and KQL, the investigation follows the evidence behind a potential information disclosure.
A document remaining in SharePoint does not mean its contents remained private.
They deleted the affected pod.
Kubernetes created a replacement.
The new container started successfully.
Everything appeared normal.
Until the suspicious behaviour returned.
Agent Foskett opened the investigation.
Was the container image compromised?
Was a Kubernetes Deployment recreating the workload?
Had a malicious configuration survived?
And what was causing the activity to repeat?
Using Azure Kubernetes Service, Microsoft Defender for Containers, Kubernetes audit logs, container telemetry and KQL, the investigation follows the evidence through pod recreation, workload configuration and persistent suspicious activity.
Rebuilding a container does not remove a threat that exists in the source.
Microsoft Intune reported it as managed.
Microsoft Entra ID recognised the device.
Conditional Access allowed the user to sign in.
Everything appeared normal.
Until the device disappeared from management.
Agent Foskett opened the investigation.
Had the device been retired or deleted?
Was it accidentally unenrolled?
Had somebody registered a different device?
And was Conditional Access still protecting access?
Using Microsoft Intune, Microsoft Entra ID sign-in logs, device audit events, Conditional Access evidence and KQL, the investigation reconstructs the device's management and authentication history.
Yesterday's compliance does not guarantee today's security.
The managed identity had no password.
No secret to steal.
No certificate to maintain.
Everything appeared secure.
Until the identity started accessing resources it had no business touching.
Agent Foskett opened the investigation.
Which Azure workload was using the identity?
What permissions had been assigned?
Had an Azure RBAC role been changed?
And what resources had the identity accessed?
Using Azure Activity Logs, Microsoft Entra managed identity sign-in logs, Azure RBAC evidence, storage access telemetry and KQL, the investigation follows how a legitimate workload identity can become a security risk.
Passwordless does not mean permissionless.
It came from a colleague.
The name was familiar.
The conversation looked normal.
There was just one problem.
The link didn't belong there.
Agent Foskett opened a new case.
Had the colleague's account been compromised?
Who clicked the suspicious link?
Did the destination attempt to steal credentials?
And had anyone authenticated afterwards?
Using Microsoft Defender XDR, Microsoft Entra ID, URL click telemetry, endpoint network activity and KQL, the investigation follows the message from delivery through to potential account compromise.
A familiar sender is not proof that a message is safe.
Microsoft Entra ID accepted the authentication.
The application continued accessing resources.
No password was involved.
Everything appeared legitimate.
Except nobody recognised the application.
Agent Foskett began investigating.
Who owned the service principal?
Who issued or uploaded the certificate?
What permissions had been granted?
And why was the application still authenticating?
Using Microsoft Entra ID, service principal sign-in logs, application audit events and KQL, the investigation follows the evidence behind certificate-based workload authentication.
A valid certificate proves the credential was accepted. It does not prove the activity was authorised.
No obvious security alert.
No suspicious file download.
No immediate indication of an attack.
Just an administrative change.
Except nobody could explain why it happened.
Agent Foskett opened the Microsoft 365 audit records.
A privileged account had modified the policy.
But was the change authorised?
Had an administrator been compromised?
And could the modification affect how long important business records were retained?
Agent Foskett examined retention policy configuration, Microsoft Purview audit events, administrator sign-ins and directory activity.
A successful policy change does not prove it was an authorised policy change.
Using Microsoft Purview, Microsoft Entra ID, audit logs and KQL, this investigation demonstrates how to reconstruct an unexpected administrative change and assess its potential effect on data retention.
An alert was generated.
An incident was created.
An automated response was initiated.
Everything appeared to be working.
Except the threat hadn't actually been contained.
Agent Foskett opened the incident timeline.
The detection was genuine.
But the response action had failed.
The device was still communicating with external infrastructure.
And the SOC dashboard hadn't made the failure immediately obvious.
Agent Foskett examined Microsoft Defender XDR alerts, Action Center records, endpoint connectivity and advanced hunting evidence.
Detecting a threat is not the same as stopping it.
Using Microsoft Defender for Endpoint, Defender XDR, DeviceProcessEvents, DeviceNetworkEvents and KQL, this investigation demonstrates why analysts must verify that response actions actually succeeded.
The answer contained sensitive business information.
The user hadn't explicitly asked for those details.
So why had the AI assistant included them?
Agent Foskett started following the evidence.
A SharePoint document contained instructions that looked like ordinary business content.
But those instructions weren't intended for a human reader.
They were designed to influence the AI assistant processing the document.
The investigation uncovered a possible prompt injection attempt.
Document permissions, version history, SharePoint audit activity and Copilot interactions became critical evidence.
The AI assistant had treated untrusted document content as an instruction.
Using Microsoft 365 Copilot, Microsoft Purview, SharePoint audit logs and KQL, Agent Foskett examines how malicious instructions hidden inside trusted-looking content can influence an AI-generated response.
The security team searched for evidence of a download.
No exported CSV.
No downloaded spreadsheet.
No obvious file transfer.
But the data was gone.
Agent Foskett started following a different trail.
An application identity had accessed the database.
API requests had retrieved unusually large volumes of customer information.
And the activity looked remarkably similar to legitimate application traffic.
The investigation moved beyond file downloads and into database auditing, API activity, service identities and application permissions.
Data does not need to become a file before it can leave an organisation.
Using Azure SQL auditing, application telemetry, Microsoft Entra ID, Microsoft Purview and KQL, Agent Foskett reconstructs how sensitive information could be extracted without a conventional download event.
The account was valid.
The authentication succeeded.
The password was accepted.
There was just one problem.
The legitimate user hadn't typed their password.
Agent Foskett started following the authentication evidence.
Was this an interactive sign-in?
Had an application authenticated using stored credentials?
Was a passwordless method involved?
Or was an existing session being mistaken for a new authentication?
The sign-in result was only the beginning.
Agent Foskett examined AuthenticationDetails, sign-in types, application activity and related events.
Successful authentication did not prove who was behind the keyboard.
This investigation uses Microsoft Entra ID, SigninLogs, AADNonInteractiveUserSignInLogs, AuthenticationDetails and KQL to examine unexpected authentication activity.
A suspicious sign-in.
A privileged account.
Enough evidence to deserve an investigation.
Minutes later, the incident was closed.
The classification looked reassuring.
False Positive.
There was only one problem.
Nobody had investigated it.
Agent Foskett followed the incident history.
The creation time.
The status change.
The classification.
The automation conditions.
The action that closed the case.
The automation rule had done exactly what it was configured to do.
But its conditions were too broad.
Then came the bigger question.
How many other incidents had been closed by the same logic?
Agent Foskett reopened the underlying evidence and reviewed the historical impact of the automation.
This investigation uses Microsoft Sentinel, SecurityIncident, SentinelAudit, automation rules and KQL to reconstruct an incident that was closed before meaningful analyst review.
Nothing appeared broken… but nothing made sense either.
This Agent Foskett briefing explains the new unified Microsoft Defender and Sentinel experience, why the portal looks different, what UEBA actually means, why dashboards appear empty at first, and the first things organisations should configure after onboarding.
This special Agent Foskett milestone reflects on the investigation mindset developed across one hundred real-world Microsoft Defender XDR, Microsoft Sentinel and Entra ID investigations. Rather than focusing on a single attack, it explores the thinking, curiosity and evidence-driven approach behind every successful investigation.
But one process launched another. Then another. Then PowerShell spawned silently in the background.
This Agent Foskett investigation follows parent and child process relationships inside Microsoft Defender XDR, using DeviceProcessEvents and KQL to uncover suspicious execution chains that dashboards may never explain.
No process creation event.
No command line showing it launch.
No obvious execution record under its own name.
It would have been easy to conclude that the file had never run.
But Agent Foskett asked a different question.
Was the file actually an executable — or was it code loaded inside another process?
DeviceImageLoadEvents contained the missing evidence.
The DLL had been loaded by a legitimate application.
Agent Foskett identified the DLL path, preserved its hash, traced the loading process and reconstructed its process lineage.
Then he investigated what happened immediately after the module was loaded.
The file never became its own process. Its code still entered one.
This investigation uses Microsoft Defender XDR, DeviceImageLoadEvents, DeviceProcessEvents, DeviceNetworkEvents and KQL to investigate suspicious DLL loading and reconstruct the endpoint timeline.
A user opened a Word document. Nobody worries when WINWORD.EXE starts.
Then Word launched PowerShell.
The parent process made sense. The child process did not.
This Agent Foskett investigation follows parent-child process relationships inside Microsoft Defender XDR using DeviceProcessEvents, ProcessCommandLine analysis and KQL to uncover suspicious execution chains hidden behind trusted applications.
The data access looked normal.
The lateral movement looked normal.
The timeline changed everything.
This Agent Foskett investigation explores how Microsoft Defender XDR, IdentityLogonEvents, DeviceEvents, CloudAppEvents and KQL can reconstruct attacks by connecting events that appear unrelated in isolation.
But one device kept reaching out to an IP address nobody recognised. Every hour. Every day.
This Agent Foskett investigation explores how Microsoft Defender XDR, DeviceNetworkEvents, DeviceProcessEvents, remote IP analysis and KQL can reveal suspicious outbound communications hidden inside normal device activity.
TCP 443.
HTTPS.
Allowed by policy.
Nothing about the firewall decision suggested anything was wrong.
But Agent Foskett wasn't investigating whether the connection was allowed.
He was investigating where it actually went.
DeviceNetworkEvents revealed the remote destination and the process responsible for the connection.
Then DeviceProcessEvents reconstructed the execution chain.
Was the process expected?
Was the destination common?
Did other devices contact it?
The protocol was normal. The destination was not.
This investigation uses Microsoft Defender XDR, DeviceNetworkEvents, DeviceProcessEvents and KQL to investigate suspicious HTTPS traffic and reconstruct the endpoint timeline.
Yet at exactly 1:22AM, a workstation connected to an IP address nobody recognised.
No alert fired. No ticket was created.
This Agent Foskett investigation explores how Microsoft Defender XDR, DeviceNetworkEvents, DeviceProcessEvents and KQL can uncover suspicious after-hours activity hidden inside normal endpoint telemetry.
Just a quiet PowerShell process using encoded commands, hidden execution and suspicious outbound behaviour that blended into normal activity.
This Agent Foskett briefing explores how Microsoft Defender telemetry can reveal suspicious execution chains even when no incident is generated.
Just a PowerShell command and a long string of characters that looked meaningless.
But the command wasn't meaningless. It was encoded.
This Agent Foskett investigation explores Base64 encoded PowerShell commands, DeviceProcessEvents, ProcessCommandLine analysis, suspicious parent processes and how Microsoft Defender XDR can reveal activity hidden inside encoded execution chains.
Just thousands of normal process events. Software updates. Management agents. Defender activity. Scheduled tasks.
Buried inside that operational noise was a single PowerShell EncodedCommand.
This Agent Foskett investigation explores PowerShell EncodedCommand activity, DeviceProcessEvents, ProcessCommandLine analysis, parent-child process relationships and how Microsoft Defender XDR can reveal suspicious execution hidden inside normal endpoint telemetry.
But the process chain was not.
Microsoft Defender XDR showed a browser process launching PowerShell, creating an execution path that deserved investigation.
This Agent Foskett investigation explores browser-spawned PowerShell, DeviceProcessEvents, parent-child process relationships, suspicious command lines, fake verification prompts and how endpoint telemetry can reveal activity hidden behind trusted applications.
But one process continued running long after the window had closed.
That single child process quietly downloaded files, contacted external systems and eventually established persistence.
This Agent Foskett investigation explores browser-based attacks, PowerShell abuse, parent-child process relationships,
DeviceProcessEvents,
DeviceNetworkEvents and how Microsoft Defender XDR helps investigators follow activity beyond the browser itself.
rundll32.exe.
The binary was Microsoft signed.
It was running from System32.
Everything appeared legitimate.
Then the command line revealed a DLL being loaded from a user-writable folder. Suddenly the investigation was no longer about the executable — it was about who told it what to run.
This Agent Foskett investigation explores Living Off The Land binaries (LOLBins), suspicious DLL execution, parent-child process relationships, DeviceProcessEvents, DeviceNetworkEvents and how Microsoft Defender XDR helps investigators uncover malicious behaviour hidden behind trusted Windows components.
Then the full command line was reviewed.
Hidden switches, encoded content and a remote download changed the entire investigation. The executable identified the tool — but the arguments revealed the intent.
This Agent Foskett investigation explores
ProcessCommandLine,
InitiatingProcessCommandLine,
suspicious PowerShell switches,
encoded commands,
parent-child process relationships,
DeviceProcessEvents,
DeviceNetworkEvents
and how Microsoft Defender XDR helps analysts uncover malicious behaviour hidden behind trusted process names.
Everything looked legitimate — until Microsoft Defender XDR telemetry showed unusual command-line arguments, suspicious DLL execution paths, strange parent process activity and unexpected outbound connections.
This Agent Foskett investigation explores how attackers abuse trusted Windows binaries like rundll32.exe, and how DeviceProcessEvents and DeviceNetworkEvents can reveal behaviour that the filename alone does not explain.
Everything appeared legitimate — until Microsoft Defender XDR telemetry revealed suspicious command lines, unusual parent process activity, LOLBin behaviour and outbound network connections that did not fit normal activity.
This Agent Foskett investigation explores how attackers abuse trusted Microsoft-signed binaries and why defenders must investigate behaviour, not just signatures.
Then CertUtil.exe downloaded a file from the internet.
The binary was trusted. The behaviour was not.
This Agent Foskett investigation explores CertUtil abuse, Living-Off-The-Land Binaries (LOLBins), DeviceProcessEvents, ProcessCommandLine analysis and how Microsoft Defender XDR can uncover suspicious downloads hidden behind legitimate Windows utilities.
But later, Microsoft Defender XDR showed suspicious file activity, PowerShell execution, outbound connections and endpoint behaviour that pointed toward something far more serious.
This Agent Foskett investigation follows attachment telemetry, SHA256 pivots, DeviceFileEvents and post-delivery activity across Microsoft Defender XDR.
Then on Wednesday afternoon, the attachment was opened.
This Agent Foskett investigation explores how Microsoft Defender XDR, EmailEvents, EmailAttachmentInfo, NetworkMessageId, timestamps and KQL can reveal when a suspicious attachment becomes dangerous long after the email was delivered.
They deleted it.
Problem solved?
Not necessarily.
The email timeline showed delivery. The attachment evidence identified the file.
Then the endpoint telemetry revealed something more important:
The attachment had already reached the device before the email disappeared from the mailbox.
Agent Foskett reconstructed what happened before deletion.
This investigation explores EmailEvents, EmailAttachmentInfo, DeviceFileEvents, DeviceProcessEvents, attachment hashes, endpoint correlation and KQL techniques for following suspicious email activity from the mailbox onto the endpoint.
This Agent Foskett briefing explains how UrlClickEvents can help defenders investigate clicked links, allowed clicks, blocked clicks, delayed user activity and post-delivery behaviour inside Microsoft Defender XDR.
All the recipient had to do was reply and begin the ownership confirmation process.
But the sender was using Gmail. The contact method was Telegram. And hidden inside the message was a tracking link.
This Agent Foskett investigation explores advance-fee social engineering, suspicious contact channels, fake unsubscribe prompts, Google Script tracking links, recipient identifiers and why engagement can be the real prize.
The email included a reference number, a compliance contact and a link to open the document.
But it wasn't coming from GEMXIT.
It was coming from halloweenville.uk.
This Agent Foskett investigation explores domain impersonation, redirect links, suspicious sender infrastructure and why routine business emails can be some of the most effective social engineering attacks.
But the sender was not Disney. The email came from an unrelated domain, used tracking infrastructure, and pushed the recipient toward suspicious external links.
This Agent Foskett investigation explores brand impersonation, sender mismatch, redirect chains and phishing analysis using Microsoft Defender XDR, EmailEvents and UrlClickEvents.
But the sender was not Microsoft. The sender was not GEMXIT.
This Agent Foskett investigation explores Microsoft brand impersonation, display name spoofing, secure document phishing lures, copied email threads and how sender evidence can expose the story the email body tried to hide.
But the scam wasn't hiding in an email attachment. It wasn't a fake login page.
It arrived as a calendar invitation.
This Agent Foskett investigation explores fake subscription renewals, calendar invitation abuse, social engineering, phone-based scams and how attackers increasingly use trusted platforms like Outlook and Google Calendar to bypass traditional email suspicion.
This is the full detection guide using real Microsoft Defender data — EmailEvents, AuthenticationDetails, DMARC failures, spoofed domains and user click activity.
👉 Built from real-world investigations where everything looked “normal”… until it wasn’t.
But the telemetry told a different story.
This Agent Foskett investigation explores SpoofedDomain, AuthenticationDetails, DMARC failures, sender alignment and Microsoft Defender XDR EmailEvents telemetry to help defenders investigate suspicious email behaviour using KQL.
But hidden inside Microsoft Defender XDR telemetry, EmailAuthenticationResults and AuthenticationDetails revealed a very different story.
This Agent Foskett investigation explores SPF, DKIM, DMARC, sender alignment, SpoofedDomain analysis and suspicious email authentication behaviour using KQL inside Microsoft Defender.
But the data told a different story — SpoofedDomain signals, EmailEvents, AuthenticationDetails, DMARC failures and suspicious sender alignment all pointed to something that did not add up.
👉 Built for the exact Microsoft Defender hunting questions security teams ask when spoofed email looks trusted.
This Agent Foskett briefing shows how modern scams use wallet connections, approval prompts and external channels to bypass traditional security controls.
But the authentication didn’t align — DMARC failed, signals conflicted, and the evidence told a different story.
This investigation shows how to read SPF, DKIM, DMARC and CompAuth in Microsoft Defender using KQL.
But behind the scenes, the domains didn’t align — what was shown and what was processed were not the same.
This investigation explains how to detect sender mismatch using EmailEvents and why it matters for spoofing detection.
But Microsoft Defender XDR showed something different.
SenderFromAddress, SenderMailFromAddress, ReturnPath, SpoofedDomain and AuthenticationDetails did not tell the same story.
This Agent Foskett investigation explores sender identity, envelope sender mismatch, spoofed email signals and why the visible From address is only one part of the email investigation.
But hidden inside AuthenticationDetails was a clue most teams never investigate.
dmarc=fail
This Agent Foskett investigation explores how Microsoft Defender XDR, EmailEvents and KQL can uncover DMARC failures, suspicious sender authentication and messages that deserve deeper investigation.
AuthenticationDetails showed a DMARC failure. Nobody investigated it.
Then somebody clicked the link.
This Agent Foskett investigation explores Microsoft Defender XDR, EmailEvents, NetworkMessageId, UrlClickEvents and KQL to determine what happened after the message reached the inbox.
It sat quietly in the inbox for three days.
Then somebody clicked the link.
This Agent Foskett investigation explores how Microsoft Defender XDR, EmailEvents, UrlClickEvents, NetworkMessageId and KQL can reveal when a delayed click turns an old email into an active security incident.
But behind the scenes, DMARC had failed — and the message was still delivered.
No block. No warning. Just a trusted email that shouldn’t have been trusted.
The email looked legitimate. Microsoft 365 delivered it successfully. No major alert triggered.
But deeper investigation exposed suspicious reply-chain behaviour, unusual URL activity, compromised sender indicators and authentication signals that did not align with normal business behaviour.
This Agent Foskett investigation explores how malicious emails can still appear trusted inside Microsoft Defender XDR even when authentication checks technically succeed.
But late at night, files started moving — dozens of downloads from SharePoint that didn’t match the user, the role, or the time.
No alert triggered. Because technically… everything was allowed.
RDP was not exposed directly to the Internet.
So how did an attacker still manage to reach it?
Agent Foskett stopped looking at the perimeter and followed the source address.
The connection came from another private IP inside Azure.
A compromised workload had used an existing private network path through virtual network peering to reach the server.
This investigation follows private IP traffic, Azure network topology, lateral movement, Microsoft Defender XDR telemetry and KQL to reconstruct the path into a supposedly isolated VM.
Today it was gone.
There was nothing left to inspect inside it.
The obvious question was:
Who deleted it?
But Agent Foskett asked another question first.
What evidence survives when the resource does not?
AzureActivity contained the management trail.
The delete operation.
The caller.
The affected resource.
The source IP context.
The correlation ID.
Agent Foskett followed the control-plane evidence backwards and forwards through the timeline.
Then he asked whether the same caller had changed anything else.
The resource was gone. The evidence wasn't.
This investigation uses Microsoft Azure, Azure Activity Log, AzureActivity and KQL to investigate resource deletion and reconstruct the control-plane timeline.
An administrator found the problem.
Corrected the configuration.
Confirmed the resource was secure again.
The ticket could have been closed.
But Agent Foskett asked one more question.
Who changed the setting in the first place?
The current configuration could only show what was true now.
So Agent Foskett went backwards.
Into AzureActivity.
The original operation.
The caller.
The caller IP.
The correlation ID.
Then the investigation expanded.
What else had the same identity changed?
The surrounding administrative activity was reconstructed.
Microsoft Entra sign-ins were examined for authentication context.
Because fixing the configuration solved only half the problem.
Was the change authorised?
Accidental?
Automated?
Or had someone used a compromised administrator identity?
This investigation uses AzureActivity, Caller, CallerIpAddress, CorrelationId, SigninLogs and KQL to reconstruct the change and investigate the identity behind it.
Its workload was supposed to be gone with it.
But while reviewing Azure Key Vault activity, Agent Foskett found an identity connected to the old system.
The compute resource was gone.
The identity trail was not.
Was this simply historical telemetry?
A surviving user-assigned managed identity?
Or an authorization path nobody had cleaned up?
Agent Foskett followed the Azure evidence.
The Key Vault operation.
The principal ID.
The managed identity.
The VM deletion.
The role assignment.
The remaining resource attachments.
Then came the distinction that changed the investigation.
Was the identity system-assigned — or user-assigned?
Because deleting a VM does not necessarily mean every identity associated with that workload disappears.
This investigation uses Microsoft Azure, Azure Key Vault, AZKVAuditLogs, AzureActivity, Azure Resource Graph and KQL to reconstruct the workload identity and authorization timeline.
GEMXIT PTY LTD GEMXIT UK LTD © GEMXIT