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implementing-web-application-logging-with-modsecurity

Configure ModSecurity WAF with the OWASP Core Rule Set (CRS) for web application audit logging, tuning SecRuleEngine, SecAuditEngine, and CRS paranoia levels to reduce false positives, and writing custom SecRules for application-specific threats. Use when deploying or tuning a ModSecurity WAF, analyzing audit logs for attack detection, or reducing CRS false positives.

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implementing-web-application-logging-with-modsecurity

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Use implementing-web-application-logging-with-modsecurity to configure audit logging and tune OWASP CRS false positives for [web server], starting in DetectionOnly mode; require my explicit approval before enabling blocking mode. Prerequisites: ModSecurity v3, OWASP CRS v4.x, and log aggregation.

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  • [web server]

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SKILL.md

name: implementing-web-application-logging-with-modsecuritydescription: Configure ModSecurity WAF with the OWASP Core Rule Set (CRS) for web  application audit logging, tuning SecRuleEngine, SecAuditEngine, and CRS paranoia  levels to reduce false positives, and writing custom SecRules for application-specific  threats. Use when deploying or tuning a ModSecurity WAF, analyzing audit logs for  attack detection, or reducing CRS false positives.domain: cybersecuritysubdomain: web-application-securitytags: - modsecurity- waf- crs- owasp- web-security- audit-logging- rule-tuningversion: '1.0'author: mahipallicense: Apache-2.0nist_ai_rmf: - MEASURE-2.7- MAP-5.1- MANAGE-2.4atlas_techniques: - AML.T0070- AML.T0066- AML.T0082nist_csf: - PR.PS-01- ID.RA-01- PR.DS-10- DE.CM-01mitre_attack: - T1190- T1059.007- T1505.003- T1083

Implementing Web Application Logging with ModSecurity

Overview

ModSecurity is an open-source WAF engine that works with Apache, Nginx, and IIS. The OWASP Core Rule Set (CRS) provides generic attack detection rules covering SQL injection, XSS, RCE, LFI, and other OWASP Top 10 attacks. ModSecurity logs full request/response data in audit logs for forensic analysis and generates alerts that feed into SIEM platforms.

When to Use

  • When deploying or configuring implementing web application logging with modsecurity 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

  • Web server (Apache 2.4+ or Nginx) with ModSecurity v3 module
  • OWASP CRS v4.x installed
  • Log aggregation infrastructure (ELK, Splunk, or Wazuh)

Steps

  1. Install ModSecurity and configure SecRuleEngine in DetectionOnly mode
  2. Deploy OWASP CRS v4 and set paranoia level (PL1-PL4)
  3. Configure SecAuditEngine for relevant-only logging
  4. Tune false positives with SecRuleRemoveById and rule exclusions
  5. Switch to blocking mode (SecRuleEngine On) after tuning period
  6. Forward audit logs to SIEM for correlation and alerting

Expected Output

ModSecurity: Warning. Pattern match "(?:union\s+select)" [file "/etc/modsecurity/crs/rules/REQUEST-942-APPLICATION-ATTACK-SQLI.conf"] [line "45"] [id "942100"] [msg "SQL Injection Attack Detected via libinjection"] [severity "CRITICAL"]