CVE-2025-27901
📋 TL;DR
IBM DB2 Recovery Expert for LUW 5.5 is vulnerable to HTTP header injection due to improper validation of HOST headers. This allows attackers to inject malicious HTTP headers, potentially leading to cross-site scripting, cache poisoning, or session hijacking attacks. Organizations running IBM DB2 Recovery Expert for Linux, UNIX and Windows version 5.5 Interim Fix 002 are affected.
💻 Affected Systems
- IBM DB2 Recovery Expert for Linux, UNIX and Windows
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could hijack user sessions, steal credentials, redirect users to malicious sites, or poison web caches to serve malicious content to multiple users.
Likely Case
Cross-site scripting attacks leading to session theft or credential harvesting from authenticated users.
If Mitigated
Limited impact if proper input validation and output encoding are implemented at the application layer.
🎯 Exploit Status
HTTP header injection vulnerabilities typically have low exploitation complexity once the attack vector is identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply the fix from IBM Security Bulletin
Vendor Advisory: https://www.ibm.com/support/pages/node/7259901
Restart Required: Yes
Instructions:
1. Review IBM Security Bulletin for specific patch details
2. Download and apply the recommended fix from IBM
3. Restart the DB2 Recovery Expert service
4. Verify the fix is applied correctly
🔧 Temporary Workarounds
Input Validation Filter
allImplement web application firewall or proxy rules to validate and sanitize HOST headers
# Example WAF rule to validate HOST headers
# Configure based on your specific WAF solution
Network Segmentation
linuxRestrict network access to DB2 Recovery Expert to trusted networks only
# Firewall rule example
iptables -A INPUT -p tcp --dport [DB2_RE_PORT] -s [TRUSTED_NETWORK] -j ACCEPT
iptables -A INPUT -p tcp --dport [DB2_RE_PORT] -j DROP
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to trusted sources only
- Deploy web application firewall with rules to detect and block HTTP header injection attempts
🔍 How to Verify
Check if Vulnerable:
Check if running IBM DB2 Recovery Expert version 5.5 Interim Fix 002 by examining version information in the application interface or configuration filesCheck Version:
# Check DB2 Recovery Expert version
# Consult IBM documentation for specific version check commands for your platformVerify Fix Applied:
Verify the patch has been applied by checking version information and testing for HTTP header injection vulnerabilities using security testing tools📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP headers in web server logs
- Multiple failed header validation attempts
- Suspicious HOST header values
Network Indicators:
- HTTP requests with malformed or unusually long HOST headers
- Requests attempting header injection patterns
SIEM Query:
source="web_server_logs" AND (HOST HEADER CONTAINS "\r\n" OR HOST HEADER CONTAINS "%0D%0A" OR HOST HEADER LENGTH > 100)