CVE-2012-4576 – CVE-2012-4576 is an input validation flaw in Fr... (How to Fix)

Q: What is the severity of CVE-2012-4576?

CVE-2012-4576 has a CVSS score of 7.8 (HIGH). CVE-2012-4576 is an input validation flaw in FreeBSD's kernel that allows local users to gain elevated privileges (root access). This vulnerability affects FreeBSD systems where local users can execute arbitrary code. Attackers must already have local access to exploit this privilege escalation.

📋 TL;DR

CVE-2012-4576 is an input validation flaw in FreeBSD's kernel that allows local users to gain elevated privileges (root access). This vulnerability affects FreeBSD systems where local users can execute arbitrary code. Attackers must already have local access to exploit this privilege escalation.

💻 Affected Systems

Products:

FreeBSD

Versions: FreeBSD 8.3-RELEASE-p2 and earlier, FreeBSD 9.0-RELEASE-p3 and earlier

Operating Systems: FreeBSD

Default Config Vulnerable: ⚠️ Yes

Notes: All default installations of affected FreeBSD versions are vulnerable. No special configuration required.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Local attacker gains full root privileges, enabling complete system compromise, data theft, persistence installation, and lateral movement.

🟠

Likely Case

Privileged local user or attacker with initial access escalates to root to bypass security controls and maintain persistence.

🟢

If Mitigated

With proper access controls and least privilege principles, impact is limited as attackers need local access first.

🌐 Internet-Facing: LOW - This is a local privilege escalation requiring existing local access, not remotely exploitable.

🏢 Internal Only: HIGH - Internal users with local shell access can exploit this to gain root privileges on affected systems.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: CONFIRMED

Unauthenticated Exploit: ✅ No

Complexity: LOW

Exploit code is publicly available and relatively simple to execute. Requires local user access to the system.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: FreeBSD 8.3-RELEASE-p3, FreeBSD 9.0-RELEASE-p4

Vendor Advisory: https://www.freebsd.org/security/advisories/FreeBSD-SA-12:09.kmem.asc

Restart Required: Yes

Instructions:

1. Update system: 'freebsd-update fetch' 2. Install updates: 'freebsd-update install' 3. Reboot system: 'shutdown -r now'

🔧 Temporary Workarounds

Restrict local user access

all

Limit shell access to trusted users only through proper access controls and monitoring.

Review /etc/passwd and /etc/group files
Use 'pw' command to manage user accounts
Implement sudo policies with 'visudo'

🧯 If You Can't Patch

Implement strict access controls to limit local user privileges and shell access
Monitor system logs for privilege escalation attempts and unusual root activity

🔍 How to Verify

Check if Vulnerable:

Check FreeBSD version with 'uname -a' and compare against affected versions (8.3-RELEASE-p2 and earlier, 9.0-RELEASE-p3 and earlier)

Check Version:

uname -a

Verify Fix Applied:

Verify system is running patched version: 'uname -a' should show 8.3-RELEASE-p3 or later, or 9.0-RELEASE-p4 or later

📡 Detection & Monitoring

Log Indicators:

Unexpected privilege escalation in auth.log
Unusual root activity from non-admin users
Failed sudo/su attempts followed by successful privilege gain

Network Indicators:

Not applicable - local exploit only

SIEM Query:

source="auth.log" AND ("privilege escalation" OR "root access" OR "sudo" OR "su") AND user!="authorized_admin_users"

📊 Metadata

CVE ID: CVE-2012-4576

CVSS v3 Score: 7.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-20

Published: December 2, 2019

Last Updated: November 21, 2024

🔗 References

http://archives.neohapsis.com/archives/bugtraq/2012-11/0089.html Broken Link
http://www.securityfocus.com/bid/56654 Third Party Advisory,VDB Entry
http://www.securitytracker.com/id?1027809 Third Party Advisory,VDB Entry
https://access.redhat.com/security/cve/cve-2012-4576 Broken Link
https://exchange.xforce.ibmcloud.com/vulnerabilities/80321 Third Party Advisory,VDB Entry
https://security-tracker.debian.org/tracker/CVE-2012-4576 Third Party Advisory
http://archives.neohapsis.com/archives/bugtraq/2012-11/0089.html Broken Link
http://www.securityfocus.com/bid/56654 Third Party Advisory,VDB Entry
http://www.securitytracker.com/id?1027809 Third Party Advisory,VDB Entry
https://access.redhat.com/security/cve/cve-2012-4576 Broken Link
https://exchange.xforce.ibmcloud.com/vulnerabilities/80321 Third Party Advisory,VDB Entry
https://security-tracker.debian.org/tracker/CVE-2012-4576 Third Party Advisory

📤 Share & Export

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⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Restrict local user access

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

🔗 Related Vulnerabilities