Pros of coreruleset

• More active development and frequent updates
• Better documentation and user guides
• Improved integration with modern web application firewalls

Cons of coreruleset

• Potentially more complex configuration for beginners
• May require more fine-tuning for specific use cases

Code Comparison

owasp-modsecurity-crs:

SecRule REQUEST_HEADERS:User-Agent "@rx (?i)(?:acunetix|nikto|sqlmap)" \
    "id:999000,\
    phase:1,\
    block,\
    t:none,\
    msg:'Malicious User Agent Detected',\
    logdata:'%{MATCHED_VAR}'"

coreruleset:

SecRule REQUEST_HEADERS:User-Agent "@rx (?i)(?:acunetix|nikto|sqlmap|nessus|nmap|openvas|qualys|burpsuite)" \
    "id:913100,\
    phase:1,\
    block,\
    t:none,\
    msg:'Found User-Agent associated with security scanner',\
    logdata:'Matched Data: %{TX.0} found within %{MATCHED_VAR_NAME}: %{MATCHED_VAR}',\
    tag:'application-multi',\
    tag:'language-multi',\
    tag:'platform-multi',\
    tag:'attack-reputation-scanner',\
    tag:'paranoia-level/1',\
    ver:'OWASP_CRS/3.3.0',\
    severity:'CRITICAL',\
    setvar:'tx.anomaly_score_pl1=+%{tx.critical_anomaly_score}'"

The coreruleset example shows more comprehensive detection patterns, additional metadata, and integration with the anomaly scoring system, reflecting its more advanced and actively maintained nature.

Pros of ModSecurity

• Core engine: Provides the fundamental web application firewall functionality
• Flexibility: Can be integrated with various web servers and platforms
• Active development: Regular updates and improvements

Cons of ModSecurity

• Limited out-of-the-box protection: Requires additional rule sets for comprehensive security
• Complexity: Can be challenging to configure and fine-tune for specific environments

Code Comparison

ModSecurity (basic rule):

SecRule REQUEST_HEADERS:User-Agent "nikto" \
    "id:1,phase:1,t:lowercase,deny,log,msg:'Nikto scanner detected'"

owasp-modsecurity-crs (CRS rule):

SecRule REQUEST_HEADERS:User-Agent "@pmFromFile scanners-user-agents.data" \
    "id:913100,phase:1,block,t:none,t:lowercase,log,msg:'Found User-Agent associated with security scanner'"

The ModSecurity example shows a basic rule to detect a specific scanner, while the CRS rule uses a more comprehensive approach with a predefined list of scanner user agents.

ModSecurity provides the core engine, while owasp-modsecurity-crs offers a comprehensive set of rules built on top of ModSecurity. CRS provides ready-to-use protection against various web application attacks, making it easier to implement robust security measures. However, ModSecurity allows for more customization and integration with different web servers, offering greater flexibility for advanced users.

Pros of naxsi

• Lightweight and designed specifically for NGINX, offering better performance
• Simpler configuration and easier to maintain
• Focuses on positive security model, potentially reducing false positives

Cons of naxsi

• Less comprehensive rule set compared to ModSecurity CRS
• Smaller community and fewer updates
• Limited compatibility with web servers other than NGINX

Code comparison

naxsi configuration example:

location / {
    SecRulesEnabled;
    DeniedUrl "/RequestDenied";
    CheckRule "$SQL >= 8" BLOCK;
    CheckRule "$RFI >= 8" BLOCK;
    CheckRule "$TRAVERSAL >= 4" BLOCK;
    CheckRule "$XSS >= 8" BLOCK;
}

owasp-modsecurity-crs configuration example:

SecRule REQUEST_HEADERS:User-Agent "nikto" \
    "id:900001,\
    phase:1,\
    deny,\
    log,\
    msg:'Nikto Scan Detected'"

Both projects aim to provide web application firewall functionality, but naxsi is more NGINX-specific and lightweight, while owasp-modsecurity-crs offers a more comprehensive and widely compatible solution. naxsi's configuration is generally simpler, but owasp-modsecurity-crs provides a more extensive rule set and broader community support.

Pros of fail2ban

• Lightweight and easy to set up, requiring minimal system resources
• Versatile, capable of protecting various services beyond just web applications
• Actively maintained with regular updates and a large community

Cons of fail2ban

• Reactive approach, blocking threats after they've been detected
• Limited in its ability to prevent sophisticated application-layer attacks
• Potential for false positives if not configured properly

Code Comparison

fail2ban configuration example:

[sshd]
enabled = true
port = ssh
filter = sshd
logpath = /var/log/auth.log
maxretry = 3

owasp-modsecurity-crs rule example:

SecRule REQUEST_HEADERS:User-Agent "@rx (?i)(?:acunetix|nikto|sqlmap)" \
    "id:999999,\
    phase:1,\
    deny,\
    status:403,\
    msg:'Malicious User Agent Detected'"

fail2ban focuses on log parsing and IP blocking, while owasp-modsecurity-crs provides detailed rules for web application firewall protection. fail2ban is more general-purpose and easier to configure, but owasp-modsecurity-crs offers more comprehensive web application security.

Pros of Suricata

• Designed for high-performance network security monitoring
• Supports multi-threading for improved processing speed
• Offers extensive protocol analysis and file extraction capabilities

Cons of Suricata

• Requires more system resources compared to ModSecurity
• Has a steeper learning curve for rule creation and management
• May generate more false positives due to its broader scope

Code Comparison

Suricata rule example:

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"SQL Injection Attempt"; 
flow:established,to_server; content:"SELECT"; nocase; 
content:"FROM"; distance:0; nocase; sid:1000001; rev:1;)

ModSecurity rule example:

SecRule ARGS "@rx (?i:select.*from)" \
    "id:1000001,\
    phase:2,\
    t:none,\
    block,\
    msg:'SQL Injection Attempt',\
    logdata:'Matched Data: %{MATCHED_VAR} found within %{MATCHED_VAR_NAME}'"

Both examples show rules for detecting SQL injection attempts, but Suricata focuses on network traffic analysis, while ModSecurity is designed for web application firewalls.