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Domain 2: Respond to Security Incidents Free ⏱ ~12 min read

Endpoint: Timeline & Live Response

When an endpoint is compromised, the device timeline tells the story. Learn how to investigate device timelines, use live response for real-time forensics, and collect investigation packages.

The device timeline: the crime scene recording

Simple explanation

The device timeline is a recording of everything that happened on a machine. Every process launched, every file created, every network connection, every registry change β€” all in chronological order.

When you investigate a compromised device, the timeline is where you reconstruct what the attacker did: what malware ran, when it ran, what it connected to, and what it changed. It is the forensic evidence that tells the story of the attack.

Live response goes further β€” it gives you a remote shell on the device so you can investigate in real-time: check running processes, download files, run scripts, and collect evidence while the device is still live.

Investigating the device timeline

What the timeline shows

Event TypeWhat It CapturesExample
Process creationNew processes launched with command linespowershell.exe -enc aQBlAHg...
File operationsFiles created, modified, deleted, or renamedC:\Temp\payload.exe created
Network connectionsOutbound/inbound connections with IPs and portsConnection to 198.51.100.42:443
Registry changesKeys created, modified, or deletedRun key added for persistence
Logon eventsUser logons, logoffs, RDP sessionsInteractive logon from 10.0.0.50
Alert eventsAlerts generated by MDE on this device”Suspicious PowerShell activity”

How to use the timeline

  1. Start at the alert timestamp β€” what was happening when the alert fired?
  2. Work backwards β€” what caused the malicious process to launch? What was the parent process?
  3. Work forwards β€” what happened after the malicious activity? Did the attacker establish persistence?
  4. Check network connections β€” did the malware phone home? What C2 server did it contact?
  5. Check file operations β€” what files were created, downloaded, or exfiltrated?

Filtering the timeline

The timeline can be overwhelming on busy servers. Use filters:

  • Event type β€” show only process creation, or only network events
  • Time range β€” narrow to the investigation window
  • Flag β€” show only flagged (suspicious) events
  • Search β€” find specific file names, process names, or IP addresses
Scenario: Elena traces malware on a payment server

Elena at Atlas Bank investigates a compromised payment server. The alert says: β€œSuspicious outbound connection from w3wp.exe.”

Timeline investigation:

  • 14:23: w3wp.exe (IIS worker process) spawns cmd.exe
  • 14:23: cmd.exe spawns powershell.exe with a Base64-encoded command
  • 14:24: powershell.exe creates C:\Windows\Temp\update.exe
  • 14:24: update.exe connects to 198.51.100.42:443 (C2 server)
  • 14:25: update.exe creates a scheduled task for persistence
  • 14:30: update.exe begins scanning internal network on port 445 (SMB)

Elena’s conclusion: Web shell uploaded to IIS β†’ command execution β†’ malware download β†’ C2 connection β†’ persistence β†’ lateral movement attempt.

Live response

Live response opens a remote shell on the device β€” without needing RDP or physical access.

What you can do in live response

CommandWhat It Does
dir / cdNavigate the file system
processesList running processes with PIDs
getfileDownload a file from the device for analysis
putfileUpload a file to the device (e.g., remediation script)
runExecute a script on the device
remediateRemove a file or kill a process
traceCollect diagnostic trace data
connectionsShow active network connections

When to use live response

  • Collect a specific file for malware analysis (the malware binary, a suspicious script)
  • Check running processes that might not appear in the timeline yet
  • Run remediation scripts to clean up persistence mechanisms
  • Collect memory dumps for advanced forensic analysis
Exam tip: live response prerequisites

Live response requires:

  1. Advanced feature enabled in MDE settings (Module 4)
  2. Unsigned script execution enabled if running custom scripts
  3. Appropriate RBAC permissions (Security Administrator or custom role)
  4. Device must be online and communicating with MDE

If an exam question says β€œan analyst cannot start a live response session,” check these prerequisites.

Investigation packages

An investigation package is an automated forensic data collection. When you trigger it, MDE gathers:

DataWhat It Contains
AutorunsPrograms that start automatically (startup, services, scheduled tasks)
Installed programsSoftware installed on the device
Network connectionsActive and recent connections with associated processes
Event logsSecurity, System, and Application event logs
Prefetch filesEvidence of program execution history
Scheduled tasksAll configured scheduled tasks
Security product statusDefender AV status, last scan time, definitions version

The package is uploaded to the Defender portal for download and offline analysis.

Timeline for the past, live response for the present, investigation packages for evidence preservation
FeatureDevice TimelineLive ResponseInvestigation Package
When to useReconstruct past eventsInvestigate in real-timeCollect forensic evidence for offline analysis
Requires device online?No β€” historical data stored in cloudYes β€” active connection neededYes β€” collection runs on device
Type of analysisChronological event reviewInteractive investigation and remediationComprehensive forensic snapshot
SpeedInstant β€” data already in cloudReal-time β€” you interact directlyMinutes β€” collection, then download
Best forUnderstanding what happenedInvestigating what is happening nowPreserving evidence for legal/compliance
Question

What six event types does the MDE device timeline capture?

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Answer

1. Process creation (with command lines). 2. File operations (create, modify, delete). 3. Network connections (IPs, ports, processes). 4. Registry changes (keys, values). 5. Logon events (interactive, RDP, network). 6. Alert events (MDE-generated alerts on this device).

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Question

What can you do in a live response session?

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Answer

Navigate the file system, list processes, download files (getfile), upload files (putfile), run scripts, remediate (remove files, kill processes), trace diagnostics, and view active network connections. Requires the Live Response advanced feature to be enabled.

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Question

What is an investigation package and when should you collect one?

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Answer

An automated forensic data collection from a device β€” includes autoruns, installed programs, network connections, event logs, prefetch files, scheduled tasks, and security product status. Collect one when you need to preserve evidence for offline analysis, legal proceedings, or compliance requirements.

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Knowledge Check

Elena needs to download a suspicious file from a compromised server for malware analysis. The server is still online but she cannot RDP into it. What should she use?

Knowledge Check

Tyler wants to understand the exact sequence of events on a compromised developer workstation β€” what processes ran, what files were created, and what network connections were made. The workstation was isolated 2 hours ago. What tool should he use?

Knowledge Check

Elena is investigating a compromised payment server at Atlas Bank. The device timeline shows the attack started 3 days ago, but the server was isolated 2 hours ago. She needs to collect a malware binary from C:\\Windows\\Temp\\update.exe for forensic analysis. Which tool should she use and why?

Next up: Device-level investigation is covered. Now let’s examine evidence and entities more deeply β€” tracing relationships between files, processes, and users across the investigation.