CVE-2020-4363
📋 TL;DR
This CVE describes a buffer overflow vulnerability in IBM DB2 database software that allows a local attacker to execute arbitrary code with root privileges. It affects DB2 versions 9.7, 10.1, 10.5, 11.1, and 11.5 on Linux, UNIX, and Windows systems. The vulnerability stems from improper bounds checking that could lead to privilege escalation.
💻 Affected Systems
- IBM DB2 for Linux, UNIX and Windows
- IBM DB2 Connect Server
📦 What is this software?
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
Db2 by Ibm
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains root privileges and executes arbitrary code, potentially leading to complete system compromise, data theft, or installation of persistent backdoors.
Likely Case
Privilege escalation from a lower-privileged local user to root, enabling unauthorized access to sensitive database data and system resources.
If Mitigated
Limited impact if proper access controls restrict local user accounts and network segmentation isolates DB2 servers.
🎯 Exploit Status
Exploitation requires local access but the buffer overflow mechanism suggests straightforward exploitation once local access is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply fixes as specified in IBM security bulletins for each version
Vendor Advisory: https://www.ibm.com/support/pages/node/6242332
Restart Required: Yes
Instructions:
1. Review IBM security advisory for your DB2 version. 2. Download and apply the appropriate fix pack or interim fix. 3. Restart DB2 services. 4. Verify the fix is applied.
🔧 Temporary Workarounds
Restrict Local Access
allLimit local user accounts on DB2 servers to only essential administrators
# Review and remove unnecessary local users
# Use 'userdel' on Linux or equivalent on other platforms
Implement Least Privilege
allEnsure DB2 runs with minimal necessary privileges and users have only required access
# Review file permissions and user privileges
# Use 'chmod' and 'chown' appropriately on Linux systems
🧯 If You Can't Patch
- Isolate DB2 servers in segmented network zones with strict access controls
- Implement comprehensive monitoring and alerting for privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check DB2 version using 'db2level' command and compare against affected versions (9.7, 10.1, 10.5, 11.1, 11.5)Check Version:
db2levelVerify Fix Applied:
Verify applied fix pack version matches or exceeds the patched version specified in IBM advisory📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation events
- Failed authentication attempts followed by successful privilege changes
- DB2 process spawning unexpected child processes
Network Indicators:
- N/A - This is a local exploit
SIEM Query:
Search for events where local user privileges escalate to root on DB2 servers, particularly following failed authentication attempts