analyzing-windows-event-logs-in-splunk

name	analyzing-windows-event-logs-in-splunk
description	Analyzes Windows Security, System, and Sysmon event logs in Splunk to detect authentication attacks, privilege escalation, persistence mechanisms, and lateral movement using SPL queries mapped to MITRE ATT&CK techniques. Use when SOC analysts need to investigate Windows-based threats, build detection queries, or perform forensic timeline analysis of Windows endpoints and domain controllers.
domain	cybersecurity
subdomain	soc-operations
tags	["soc","splunk","windows-events","sysmon","event-logs","mitre-attack","active-directory"]
version	1.0
author	mahipal
license	Apache-2.0
d3fend_techniques	["Restore Access","Password Authentication","Biometric Authentication","Strong Password Policy","Restore User Account Access"]
nist_csf	["DE.CM-01","DE.AE-02","RS.MA-01","DE.AE-06"]

Analyzing Windows Event Logs in Splunk

When to Use

Use this skill when:

• SOC analysts investigate alerts related to Windows authentication, process execution, or AD changes
• Detection engineers build SPL queries for Windows-based threat detection
• Incident responders need forensic timelines of Windows endpoint or domain controller activity
• Periodic threat hunting targets Windows-specific ATT&CK techniques

Do not use for Linux/macOS endpoint analysis or network-only investigations.

Prerequisites

• Splunk with Windows Event Log data ingested (sourcetype WinEventLog:Security, WinEventLog:System, XmlWinEventLog:Microsoft-Windows-Sysmon/Operational)
• Sysmon deployed on endpoints with SwiftOnSecurity or Olaf Hartong configuration
• CIM data model acceleration for Endpoint and Authentication data models
• Knowledge of Windows Security Event IDs and Sysmon event types

Workflow

Step 1: Authentication Attack Detection

Brute Force Detection (EventCode 4625 — Failed Logon):

index=wineventlog sourcetype="WinEventLog:Security" EventCode=4625
| stats count, dc(TargetUserName) AS unique_users, values(TargetUserName) AS targeted_users
  by src_ip, Logon_Type, Status
| where count > 20
| eval attack_type = case(
    Logon_Type=3, "Network Brute Force",
    Logon_Type=10, "RDP Brute Force",
    Logon_Type=2, "Interactive Brute Force",
    1=1, "Other"
  )
| eval status_meaning = case(
    Status="0xc000006d", "Bad Username or Password",
    Status="0xc000006a", "Incorrect Password (valid user)",
    Status="0xc0000234", "Account Locked Out",
    Status="0xc0000072", "Account Disabled",
    1=1, Status
  )
| sort - count
| table src_ip, attack_type, status_meaning, count, unique_users, targeted_users

Password Spray Detection:

index=wineventlog sourcetype="WinEventLog:Security" EventCode=4625 Logon_Type=3
| bin _time span=10m
| stats dc(TargetUserName) AS unique_users, count AS total_attempts,
  values(TargetUserName) AS users_targeted by src_ip, _time
| where unique_users > 10 AND total_attempts < unique_users * 3
| eval spray_confidence = if(unique_users > 25, "HIGH", "MEDIUM")

Successful Logon After Failures (Compromise Indicator):

index=wineventlog sourcetype="WinEventLog:Security"
(EventCode=4625 OR EventCode=4624) src_ip!="127.0.0.1"
| sort _time
| stats earliest(_time) AS first_seen, latest(_time) AS last_seen,
  sum(eval(if(EventCode=4625,1,0))) AS failures,
  sum(eval(if(EventCode=4624,1,0))) AS successes
  by src_ip, TargetUserName, ComputerName
| where failures > 10 AND successes > 0
| eval time_to_success = round((last_seen - first_seen)/60, 1)
| sort - failures