CVE-2008-3656 — AI Deep Analysis Summary

🚨 **Essence**: A Denial of Service (DoS) flaw in Ruby's WEBrick. 📉 **Consequences**: Remote attackers can exhaust CPU resources via crafted HTTP requests, causing service unavailability. 💥 No data theft, just a crash.

🛡️ **Root Cause**: Algorithmic weakness in `WEBrick::HTTPUtils.split_header_value`. 🐛 **Flaw**: Vulnerable to **ReDoS** (Regular Expression Denial of Service) via backtracking.…

📦 **Affected**: Ruby versions 1.8.5 and earlier. 📦 1.8.6 up to p286. 📦 1.8.7 up to p71. 📦 Ruby 1.9 up to r18423. 🌐 Specifically impacts the **WEBrick** HTTP server component.

🕵️ **Action**: Attackers send malicious HTTP headers. 📉 **Impact**: CPU usage spikes to 100%. 🚫 **Result**: Service becomes unresponsive (DoS). 🔒 **Privileges**: Remote, unauthenticated.…

🔓 **Threshold**: **LOW**. 🌐 **Auth**: None required. 📡 **Config**: Any public WEBrick server is exposed. 🎯 **Vector**: Network-based HTTP request. Easy to trigger from anywhere.

📜 **Exploit Status**: Public advisories exist (Secunia, Bugtraq, X-Force). 🧪 **PoC**: Specific backtracking regex patterns are known.…

🔍 **Check**: Scan for Ruby WEBrick servers. 📋 **Version**: Verify Ruby version < 1.8.7-p72 or < 1.9 r18424. 📡 **Test**: Send HTTP requests with complex header values to observe CPU spikes.…

✅ **Fixed**: Yes. 📅 **Date**: Advisories published Aug 2008. 🔄 **Action**: Upgrade Ruby to patched versions (e.g., 1.8.7-p72+). 🛡️ **Vendor**: Ruby core team addressed the regex weakness.

🚧 **No Patch?**: Upgrade Ruby immediately. 🛑 **Mitigation**: Disable WEBrick if not needed. 🛡️ **WAF**: Block suspicious HTTP headers with complex regex patterns.…

⚠️ **Priority**: **HIGH** for legacy systems. 📉 **Risk**: Easy DoS attack. 🕰️ **Age**: Old (2008), but critical for unpatched legacy Ruby apps. 🚀 **Action**: Patch now if running vulnerable versions.…