What it does. Write multi-event correlation rules in Splunk SPL and Sigma format that Part of mukul975/Anthropic-Cybersecurity-Skills (817 security skills) (mukul975/Anthropic-Cybersecurity-Skills).

Install

• npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-siem-correlation-rules-for-apt, or copy the skill folder into ~/.claude/skills/implementing-siem-correlation-rules-for-apt/.
• Raw file: curl -sL https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/HEAD/skills/implementing-siem-correlation-rules-for-apt/SKILL.md

SKILL.md (verbatim)

name: implementing-siem-correlation-rules-for-apt
description: Write multi-event correlation rules in Splunk SPL and Sigma format that
  detect APT lateral movement by chaining Windows authentication events (4624, 4648),
  process execution (4688, Sysmon Event 1), and network connections (Sysmon Event 3)
  across hosts within sliding time windows. Use when building SIEM correlation searches
  to surface multi-stage attack sequences that single-event detections miss, such
  as pass-the-hash or lateral movement chains.
domain: cybersecurity
subdomain: security-operations
tags:
- siem
- correlation-rules
- apt-detection
- lateral-movement
- windows-event-logs
- security-operations
version: '1.0'
author: mahipal
license: Apache-2.0
nist_csf:
- DE.CM-01
- RS.MA-01
- GV.OV-01
- DE.AE-02
mitre_attack:
- T1078
- T1190
- T1059
- T1021
- T1550

Implementing SIEM Correlation Rules for APT

When to Use

• When deploying or configuring implementing siem correlation rules for apt capabilities in your environment
• When establishing security controls aligned to compliance requirements
• When building or improving security architecture for this domain
• When conducting security assessments that require this implementation

Prerequisites

• Familiarity with security operations concepts and tools
• Access to a test or lab environment for safe execution
• Python 3.8+ with required dependencies installed
• Appropriate authorization for any testing activities

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 | near service_installed
level: high

Other files in this skill

• LICENSE
• references/api-reference.md
• scripts/agent.py

references/api-reference.md (verbatim)

API Reference: SIEM Correlation Rules for APT

Splunk REST API

Authentication

POST /services/auth/login
Body: username=<user>&password=<pass>
Returns: { "sessionKey": "<token>" }
Header: Authorization: Splunk <sessionKey>

Saved Searches (Correlation Rules)

POST /services/saved/searches
Parameters: name, search, cron_schedule, dispatch.earliest_time,
  dispatch.latest_time, alert.severity, action.notable (1=enabled),
  action.notable.param.severity, action.notable.param.security_domain
GET /services/saved/searches?output_mode=json&count=0

Search Jobs

POST /services/search/jobs
Body: search=<SPL>, earliest_time, latest_time, output_mode=json
Returns: { "sid": "<job_id>" }
GET /services/search/jobs/<sid>?output_mode=json
GET /services/search/jobs/<sid>/results?output_mode=json&count=<n>

Sigma Rule Format (YAML)

title: <string>
status: experimental|test|stable
logsource:
  product: windows
  service: sysmon|security
detection:
  selection: { EventID: [1,3] }
  condition: selection
level: low|medium|high|critical
tags: [attack.t1021.001]

sigma-cli Conversion

sigma convert -t splunk -p sysmon rule.yml
sigma convert -t elastic-eql -p sysmon rule.yml

Key Windows Event IDs for Lateral Movement

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