CVE-2011-2921
📋 TL;DR
CVE-2011-2921 is a privilege escalation vulnerability in ktsuss versions 1.4 and earlier. The software runs with root privileges but fails to drop them before executing user-specified commands, allowing local users to execute arbitrary commands with root privileges. This affects any system running vulnerable ktsuss versions with the SUID bit set.
💻 Affected Systems
- ktsuss
📦 What is this software?
Ktsuss by Ktsuss Project
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains full root access to the system, enabling complete compromise including data theft, persistence installation, and lateral movement.
Likely Case
Local user escalates privileges to root, gaining administrative control over the affected system.
If Mitigated
Attack fails due to proper privilege separation or lack of SUID permissions on ktsuss binary.
🎯 Exploit Status
Exploitation is straightforward - attacker simply runs ktsuss with crafted command arguments. Requires local shell access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: ktsuss 1.5 and later
Vendor Advisory: https://security-tracker.debian.org/tracker/CVE-2011-2921
Restart Required: No
Instructions:
1. Update ktsuss to version 1.5 or later using your distribution's package manager. 2. For Debian/Ubuntu: sudo apt-get update && sudo apt-get install ktsuss. 3. For Red Hat/CentOS: sudo yum update ktsuss. 4. Verify the SUID bit is removed or the binary properly drops privileges.
🔧 Temporary Workarounds
Remove SUID bit from ktsuss
linuxRemove the setuid permission from the ktsuss binary to prevent privilege escalation
sudo chmod u-s /usr/bin/ktsuss
Uninstall ktsuss
linuxRemove the vulnerable software entirely if not needed
sudo apt-get remove ktsuss
sudo yum remove ktsuss
🧯 If You Can't Patch
- Remove SUID permissions from ktsuss binary using: chmod u-s /usr/bin/ktsuss
- Restrict access to ktsuss binary to only trusted users using filesystem permissions
🔍 How to Verify
Check if Vulnerable:
Check if ktsuss has SUID bit set and is version 1.4 or earlier: ls -la /usr/bin/ktsuss | grep '^...s' && ktsuss --versionCheck Version:
ktsuss --version 2>/dev/null || dpkg -l ktsuss 2>/dev/null || rpm -q ktsuss 2>/dev/nullVerify Fix Applied:
Verify ktsuss version is 1.5+ and SUID bit is removed or properly handled: ktsuss --version && ls -la /usr/bin/ktsuss📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation via ktsuss in system logs
- Multiple failed or successful ktsuss executions from non-admin users
Network Indicators:
- N/A - local exploitation only
SIEM Query:
process.name:"ktsuss" AND user.name!="root" AND process.parent.name!="sudo"🔗 References
- http://packetstormsecurity.com/files/154307/ktsuss-Suid-Privilege-Escalation.html
- https://access.redhat.com/security/cve/cve-2011-2921
- https://security-tracker.debian.org/tracker/CVE-2011-2921
- http://packetstormsecurity.com/files/154307/ktsuss-Suid-Privilege-Escalation.html
- https://access.redhat.com/security/cve/cve-2011-2921
- https://security-tracker.debian.org/tracker/CVE-2011-2921
