CVE-2025-36136
📋 TL;DR
A local user on systems running vulnerable IBM Db2 versions can cause a denial of service by exploiting a flaw in the database monitor script. The script incorrectly detects that the instance is still starting under specific conditions, allowing disruption of database availability. This affects Db2 11.5.0-11.5.9 and 12.1.0-12.1.3 on Linux, UNIX, and Windows platforms.
💻 Affected Systems
- IBM Db2
- DB2 Connect Server
📦 What is this software?
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
⚠️ Risk & Real-World Impact
Worst Case
Complete database unavailability affecting all applications and users dependent on the Db2 instance, potentially causing business disruption.
Likely Case
Temporary database service interruption affecting local users and applications until manual intervention restores service.
If Mitigated
Minimal impact with proper access controls limiting local user privileges and monitoring systems detecting abnormal behavior.
🎯 Exploit Status
Exploitation requires local access to trigger the flawed script logic under specific conditions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply IBM Db2 fixes as specified in the vendor advisory
Vendor Advisory: https://www.ibm.com/support/pages/node/7250485
Restart Required: Yes
Instructions:
1. Review IBM advisory for specific fix details. 2. Apply the appropriate Db2 fix pack or interim fix. 3. Restart the Db2 instance to apply changes.
🔧 Temporary Workarounds
Restrict local user access
allLimit local user privileges on Db2 servers to prevent unauthorized users from triggering the vulnerable script.
# Review and restrict user permissions using OS-specific access controls
Monitor script execution
allImplement monitoring for database monitor script executions to detect abnormal patterns.
# Set up audit logging for Db2 script executions
🧯 If You Can't Patch
- Implement strict access controls to limit which local users can interact with Db2 processes
- Deploy additional monitoring for database availability and script execution patterns
🔍 How to Verify
Check if Vulnerable:
Check Db2 version using 'db2level' command and compare against affected versions (11.5.0-11.5.9, 12.1.0-12.1.3)Check Version:
db2levelVerify Fix Applied:
Verify applied fix by checking version after patching and confirming database monitor script behavior is normal📡 Detection & Monitoring
Log Indicators:
- Unusual database monitor script executions
- Database instance restart failures
- Denial of service events in Db2 logs
Network Indicators:
- Database connection failures from applications
SIEM Query:
source="db2*" AND (event="instance restart" OR event="monitor script")