Imported from mukul975/anthropic-cybersecurity-skills (skills/detecting-lateral-movement-with-splunk/SKILL.md). Install upstream with npx skills add mukul975/anthropic-cybersecurity-skills --skill detecting-lateral-movement-with-splunk. Copyright stays with the author (Apache-2.0).

Detecting Lateral Movement with Splunk

When to Use

• When hunting for adversary movement between compromised systems
• After detecting credential theft to trace subsequent lateral activity
• When investigating unusual authentication patterns across the network
• During incident response to scope the breadth of compromise
• When proactively hunting for TA0008 (Lateral Movement) techniques

Prerequisites

• Splunk Enterprise or Splunk Cloud with Windows event data ingested
• Windows Security Event Logs forwarded (4624, 4625, 4648, 4672, 4768, 4769)
• Sysmon deployed for process creation and network connection data
• Network flow data or firewall logs for SMB/RDP/WinRM correlation
• Active Directory user and group membership reference data

Workflow

1. Define Lateral Movement Scope: Identify which lateral movement techniques to hunt (RDP, SMB/Admin Shares, WinRM, PsExec, WMI, DCOM, SSH).
2. Query Authentication Events: Use SPL to search for Type 3 (Network) and Type 10 (RemoteInteractive) logons across the environment.
3. Build Authentication Graphs: Map source-to-destination authentication relationships to identify unusual connection patterns.
4. Detect First-Time Relationships: Identify new source-destination pairs that have not been seen in the historical baseline.
5. Correlate with Process Activity: Link authentication events to subsequent process creation on destination hosts.
6. Identify Anomalous Patterns: Flag lateral movement to sensitive servers, unusual hours, service account misuse, or rapid multi-host access.
7. Report and Contain: Document lateral movement path, affected systems, and coordinate containment response.

Key Concepts

Tools & Systems

Common Scenarios

1. PsExec Lateral Movement: Adversary uses PsExec to execute commands on remote systems via SMB, generating Type 3 logon with ADMIN$ share access.
2. RDP Pivoting: Attacker RDPs to internal systems using stolen credentials, creating Type 10 logon events.
3. WMI Remote Execution: Adversary uses WMIC process call create to spawn processes on remote hosts.
4. WinRM PowerShell Remoting: Attacker uses Enter-PSSession or Invoke-Command to execute code on remote systems.
5. Pass-the-Hash via SMB: Compromised NTLM hashes used to authenticate to remote systems without knowing the plaintext password.

Output Format

Hunt ID: TH-LATMOV-[DATE]-[SEQ]
Movement Type: [RDP/SMB/WinRM/WMI/DCOM/PsExec]
Source Host: [Hostname/IP]
Destination Host: [Hostname/IP]
Account Used: [Username]
Logon Type: [3/10/other]
First Seen: [Timestamp]
Event Count: [Number of events]
Risk Level: [Critical/High/Medium/Low]
Lateral Movement Path: [A -> B -> C -> D]