implementing-siem-correlation-rules-for-apt

name	implementing-siem-correlation-rules-for-apt
description	Write multi-event correlation rules that detect APT lateral movement by chaining Windows authentication events, process execution telemetry, and network connection logs across hosts. Uses Splunk SPL and Sigma rule format to correlate Event IDs 4624, 4648, 4688, and Sysmon Events 1/3 within sliding time windows to surface attack sequences invisible to single-event detections.
domain	cybersecurity
subdomain	security-operations
tags	["implementing","siem","correlation","rules"]
version	1.0
author	mahipal
license	Apache-2.0

Instructions

1. Install dependencies: pip install requests pyyaml sigma-cli
2. Connect to the Splunk REST API and define correlation searches that chain multiple event types across hosts.
3. Build Sigma rules in YAML that express multi-step detection logic for lateral movement patterns:
   • RDP logon (4624 LogonType=10) followed by service installation (7045) on same target within 15 minutes
   • Pass-the-Hash: NTLM logon (4624 LogonType=3) followed by process creation (4688) of admin tools
   • PsExec-style: Named pipe creation (Sysmon 17/18) correlated with remote service creation (7045)
4. Convert Sigma rules to Splunk SPL using sigma-cli convert.
5. Deploy correlation searches to Splunk ES via the REST API.
6. Run the agent to generate and install correlation rules, then audit existing rules for coverage gaps.

python scripts/agent.py --splunk-url https://localhost:8089 --username admin --password changeme --output correlation_report.json

Examples

Detect RDP Lateral Movement Chain

index=wineventlog (EventCode=4624 Logon_Type=10) OR (EventCode=7045)
| transaction Computer maxspan=15m startswith=(EventCode=4624) endswith=(EventCode=7045)
| where eventcount >= 2
| table _time Computer Account_Name ServiceName

Sigma Rule for PsExec Lateral Movement

title: PsExec Lateral Movement Detection
logsource:
  product: windows
  service: sysmon
detection:
  pipe_created:
    EventID: 17
    PipeName|startswith: '\PSEXESVC'
  service_installed:
    EventID: 7045
    ServiceFileName|contains: 'PSEXESVC'
  timeframe: 5m
  condition: pipe_created