Analyzing Web Server Logs for Intrusion
When to Use
- When investigating security incidents that require analyzing web server logs for intrusion
- 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
- 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
- Install dependencies:
pip install geoip2 user-agents
- Collect web server access logs in Combined Log Format (Apache) or Nginx default format.
- Parse each log entry extracting: IP, timestamp, method, URI, status code, response size, user-agent, referer.
- Apply detection rules:
- SQL injection:
UNION SELECT, OR 1=1, ' OR ', hex encoding patterns
- LFI/Path traversal:
../, /etc/passwd, /proc/self, php://filter
- XSS:
<script>, javascript:, onerror=, onload=
- Scanner signatures: nikto, sqlmap, dirbuster, gobuster, wfuzz user-agents
- Brute force: >50 POST requests to login endpoints from same IP in 5 minutes
- Enrich with GeoIP data and generate a prioritized findings report.
python scripts/agent.py --log-file /var/log/nginx/access.log --geoip-db GeoLite2-City.mmdb --output web_intrusion_report.json
Examples
Detect SQLi in URI
192.168.1.100 - - [15/Jan/2024:10:30:45 +0000] "GET /products?id=1' UNION SELECT username,password FROM users-- HTTP/1.1" 200 4532
Scanner User-Agent Detection
Nikto/2.1.6, sqlmap/1.7, DirBuster-1.0-RC1, gobuster/3.1.0