CVE-2025-1991
📋 TL;DR
IBM Informix Dynamic Server contains an integer underflow vulnerability when processing network packets, allowing remote attackers to cause denial of service. This affects versions 12.10, 14.10, and 15.0 of the database server.
💻 Affected Systems
- IBM Informix Dynamic Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption of IBM Informix Dynamic Server, making the database unavailable to all applications and users.
Likely Case
Service crashes or hangs requiring manual restart, causing temporary database unavailability.
If Mitigated
Limited impact with proper network segmentation and access controls preventing unauthorized access to database ports.
🎯 Exploit Status
Integer underflow vulnerabilities typically require sending malformed packets to trigger the condition.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply fixes from IBM security advisory
Vendor Advisory: https://www.ibm.com/support/pages/node/7238455
Restart Required: Yes
Instructions:
1. Review IBM advisory 7238455. 2. Download appropriate fix packs for your version. 3. Apply patches following IBM documentation. 4. Restart Informix services.
🔧 Temporary Workarounds
Network Access Restriction
allRestrict network access to Informix ports to only trusted sources
# Use firewall rules to restrict access to Informix ports (e.g., 9088, 9090)
# Example: iptables -A INPUT -p tcp --dport 9088 -s trusted_ip -j ACCEPT
# Example: iptables -A INPUT -p tcp --dport 9088 -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation and firewall rules to limit access to Informix ports
- Monitor for unusual traffic patterns or connection attempts to database ports
🔍 How to Verify
Check if Vulnerable:
Check Informix version: onmserver -version or SELECT DBINFO('version','full') FROM systables WHERE tabid=1Check Version:
onmserver -versionVerify Fix Applied:
Verify version after patching and check IBM advisory for specific fix versions📡 Detection & Monitoring
Log Indicators:
- Informix service crashes or restarts
- Error messages related to packet processing or memory issues
Network Indicators:
- Unusual traffic patterns to Informix ports
- Multiple connection attempts with malformed packets
SIEM Query:
source="informix.log" AND ("crash" OR "restart" OR "abnormal termination")