CVE-2021-29706
📋 TL;DR
A vulnerability in IBM AIX's trace facility allows local non-privileged users to access sensitive information or cause denial of service. This affects AIX 7.1 systems where the trace facility is enabled. Attackers must have local access to exploit this vulnerability.
💻 Affected Systems
- IBM AIX
📦 What is this software?
Aix by Ibm
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains unauthorized access to sensitive system information or crashes the system causing complete denial of service.
Likely Case
Local user accesses privileged information they shouldn't have access to, potentially leading to privilege escalation or data exposure.
If Mitigated
With proper access controls and patching, impact is limited to authorized users only accessing their own trace data.
🎯 Exploit Status
Requires local user access and knowledge of the trace facility. No public exploit code available as of analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: AIX 7.1 TL5 SP11 or later
Vendor Advisory: https://www.ibm.com/support/pages/node/6464369
Restart Required: Yes
Instructions:
1. Download the appropriate APAR fix from IBM Fix Central. 2. Install the fix using installp command. 3. Reboot the system to apply changes.
🔧 Temporary Workarounds
Disable trace facility
aixTemporarily disable the trace facility to prevent exploitation
trace -d
trcstop
Restrict trace access
aixLimit which users can access trace facility
chmod 700 /usr/bin/trace
chmod 700 /usr/bin/trcstop
🧯 If You Can't Patch
- Implement strict access controls to limit who can run trace commands
- Monitor trace facility usage and audit logs for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check AIX version with 'oslevel -s' and verify if below 7100-05-11Check Version:
oslevel -sVerify Fix Applied:
Verify APAR IJ29838 is installed using 'instfix -ik IJ29838'📡 Detection & Monitoring
Log Indicators:
- Unauthorized trace command executions
- Multiple trace process failures
- System crashes following trace operations
Network Indicators:
- None - local exploit only
SIEM Query:
source="aix_system_logs" AND (event="trace" OR event="trcstop") AND user!="root" AND user!="authorized_users"