Cyberstudy
Supplementary — not from your PDF Intermediate ~35 min

Investigate Windows sign-in events

Find your own successful and failed sign-ins and privileged sessions in the Windows Security log, then filter them the way a SOC analyst would.

Environment

Your own Windows PC or a Windows VM. Use PowerShell as Administrator.

Before you start

  • Read Log Data (p.317), Host Operating System Logs (p.318) and Security Information and Event Management (p.325).

You will

  • Find events 4624, 4625 and 4672
  • Filter by time and event ID
  • Explain the fields that matter in an investigation

Steps

  1. 1

    Lock your screen (Win+L), mistype your own password once, then sign in properly.

  2. 2

    Open Event Viewer → Windows Logs → Security and filter the current log for Event IDs 4624, 4625 and 4672.

  3. 3

    Open your 4625 (failed logon) event and note the Account Name, Failure Reason, Logon Type and time.

  4. 4

    Do the same in PowerShell: Get-WinEvent -FilterHashtable @{LogName='Security'; Id=4625; StartTime=(Get-Date).AddHours(-1)} | Format-List TimeCreated, Message.

  5. 5

    Count today's successful sign-ins: (Get-WinEvent -FilterHashtable @{LogName='Security'; Id=4624; StartTime=(Get-Date).Date}).Count.

  6. 6

    Write one detection rule in plain English, for example 'alert if more than 10 failed logons for one account in 5 minutes', and note what false positives it might produce.

Check your understanding

  • ?What does Event ID 4672 tell you?
  • ?Why do SIEMs collect these logs centrally instead of leaving them on each PC?
  • ?How would you tune your alert rule to cut false positives?