CVE-2021-45417
📋 TL;DR
CVE-2021-45417 is a heap-based buffer overflow vulnerability in AIDE (Advanced Intrusion Detection Environment) that allows local users to escalate privileges to root by exploiting crafted file metadata like XFS extended attributes or tmpfs ACLs. This affects systems running AIDE for file integrity monitoring where local attackers can gain full system control.
💻 Affected Systems
- AIDE (Advanced Intrusion Detection Environment)
📦 What is this software?
Advanced Intrusion Detection Environment by Advanced Intrusion Detection Environment Project
View all CVEs affecting Advanced Intrusion Detection Environment →
Fedora by Fedoraproject
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains full root privileges, compromising the entire system, installing persistent backdoors, accessing all data, and pivoting to other systems.
Likely Case
Privileged local user or attacker with initial access escalates to root to maintain persistence, bypass security controls, and access sensitive information.
If Mitigated
With proper access controls and minimal local user accounts, impact is limited to systems where attackers already have local access but cannot achieve full compromise.
🎯 Exploit Status
Exploit requires local access and knowledge of file system metadata manipulation. Proof-of-concept details are publicly available in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.17.4 and later
Vendor Advisory: https://www.ipi.fi/pipermail/aide/2022-January/001713.html
Restart Required: No
Instructions:
1. Update AIDE to version 0.17.4 or later using your distribution's package manager. 2. For Debian/Ubuntu: 'sudo apt update && sudo apt upgrade aide'. 3. For RHEL/CentOS: 'sudo yum update aide'. 4. Reinitialize the AIDE database: 'sudo aideinit'. 5. Verify the update with 'aide --version'.
🔧 Temporary Workarounds
Restrict local user access
linuxLimit local user accounts to minimize attack surface for privilege escalation.
sudo userdel <unnecessary_user>
sudo passwd -l <user_to_lock>
Disable AIDE temporarily
linuxStop AIDE service if patching is delayed, but note this reduces file integrity monitoring.
sudo systemctl stop aide
sudo systemctl disable aide
🧯 If You Can't Patch
- Remove unnecessary local user accounts to reduce attack vectors.
- Implement strict access controls and monitor for suspicious local privilege escalation attempts.
🔍 How to Verify
Check if Vulnerable:
Run 'aide --version' and check if version is below 0.17.4. Also check if AIDE is installed with 'which aide' or 'dpkg -l | grep aide'.Check Version:
aide --versionVerify Fix Applied:
After updating, run 'aide --version' to confirm version 0.17.4 or higher. Test AIDE functionality with 'sudo aide --check'.📡 Detection & Monitoring
Log Indicators:
- Unexpected AIDE process crashes or errors in system logs
- Sudden privilege escalation events in audit logs
- Unauthorized root access from non-privileged users
Network Indicators:
- None - this is a local exploit with no network indicators
SIEM Query:
source="*aide*" AND (error OR crash) OR event_type="privilege_escalation" AND user!="root"🔗 References
- http://www.openwall.com/lists/oss-security/2022/01/20/3
- https://lists.debian.org/debian-lts-announce/2022/01/msg00024.html
- https://security.gentoo.org/glsa/202311-07
- https://www.debian.org/security/2022/dsa-5051
- https://www.ipi.fi/pipermail/aide/2022-January/001713.html
- https://www.openwall.com/lists/oss-security/2022/01/20/3
- http://www.openwall.com/lists/oss-security/2022/01/20/3
- https://lists.debian.org/debian-lts-announce/2022/01/msg00024.html
- https://security.gentoo.org/glsa/202311-07
- https://www.debian.org/security/2022/dsa-5051
- https://www.ipi.fi/pipermail/aide/2022-January/001713.html
- https://www.openwall.com/lists/oss-security/2022/01/20/3
