/analyzing-web-server-logs-for-intrusion

name: analyzing-web-server-logs-for-intrusion
description: Parse Apache and Nginx access logs to detect SQL injection attempts, local file inclusion, directory traversal,
  web scanner fingerprints, and brute-force patterns. Uses regex-based pattern matching against OWASP attack signatures, GeoIP
  enrichment for source attribution, and statistical anomaly detection for request frequency and response size outliers.
domain: cybersecurity
subdomain: security-operations
tags:
- analyzing
- web
- server
- logs
version: '1.0'
author: mahipal
license: Apache-2.0
nist_csf:
- DE.CM-01
- RS.MA-01
- GV.OV-01
- DE.AE-02

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

1. Install dependencies: `pip install geoip2 user-agents` 2. Collect web server access logs in Combined Log Format (Apache) or Nginx default format. 3. Parse each log entry extracting: IP, timestamp, method, URI, status code, response size, user-agent, referer. 4. 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

5. 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