hunting-for-unusual-service-installations

name	hunting-for-unusual-service-installations
description	Detect suspicious Windows service installations (MITRE ATT&CK T1543.003) by parsing System event logs for Event ID 7045, analyzing service binary paths, and identifying indicators of persistence mechanisms. Use when detecting suspicious windows service installations (mitre att&ck t1543.003) by parsing.
domain	cybersecurity
subdomain	threat-hunting
tags	["threat-hunting","T1543.003","service-installation","persistence","Event-7045","Sysmon","Windows-services"]
version	1.0
author	oyi77
license	Apache-2.0
d3fend_techniques	["Platform Hardening","System Configuration Permissions","Restore Object","Restore Database","Asset Inventory"]
nist_csf	["DE.CM-01","DE.AE-02","DE.AE-07","ID.RA-05"]

Hunting for Unusual Service Installations

Overview

Attackers frequently install malicious Windows services for persistence and privilege escalation (MITRE ATT&CK T1543.003 — Create or Modify System Process: Windows Service). Event ID 7045 in the System event log records every new service installation. This skill parses .evtx log files to extract service installation events, flags suspicious binary paths (temp directories, PowerShell, cmd.exe, encoded commands), and correlates with known attack patterns.

When to Use

Trigger phrases:

• "hunting for unusual service installations"

• "Detect suspicious Windows service installations (MITRE ATT&CK T1543"

• When investigating security incidents that require hunting for unusual service installations

• When building detection rules or threat hunting queries for this domain

• When SOC analysts need structured procedures for this analysis type

• When validating security monitoring coverage for related attack techniques

Prerequisites

• Python 3.9+ with python-evtx, lxml
• Windows System event log (.evtx) files
• Access to live System event log (optional, for real-time monitoring)
• Sysmon logs for enhanced process tracking (optional)

Steps

# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}

1. Parse System.evtx for Event ID 7045 (new service installed)
2. Extract service name, binary path, service type, and account