CVE-2023-6531
📋 TL;DR
A use-after-free vulnerability in the Linux kernel's Unix domain socket garbage collector allows local attackers to potentially escalate privileges or cause denial of service. The race condition occurs when the garbage collector deletes socket buffers while they're being read. This affects Linux systems with Unix domain sockets enabled.
💻 Affected Systems
- Linux Kernel
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to root, kernel panic causing system crash, or arbitrary code execution in kernel context.
Likely Case
Local denial of service through kernel panic or system instability, with privilege escalation requiring additional exploitation techniques.
If Mitigated
Minimal impact with proper access controls limiting local user accounts and SELinux/AppArmor enforcement.
🎯 Exploit Status
Exploit requires local access and race condition triggering. Proof-of-concept code is publicly available in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Varies by distribution - check vendor advisories (e.g., kernel 6.6.13+, RHEL kernel-5.14.0-427.18.1.el9_4)
Vendor Advisory: https://access.redhat.com/errata/RHSA-2024:2394
Restart Required: Yes
Instructions:
1. Check your distribution's security advisory. 2. Update kernel package via package manager. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Restrict local user access
linuxLimit number of local user accounts and implement strict access controls
Enable kernel security modules
linuxUse SELinux or AppArmor to restrict process capabilities
setenforce 1
systemctl enable apparmor
🧯 If You Can't Patch
- Implement strict access controls to limit local user accounts
- Use security modules (SELinux/AppArmor) with restrictive policies
🔍 How to Verify
Check if Vulnerable:
Check kernel version against vendor advisories: uname -r and compare to patched versionsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version after update matches patched version from vendor advisory📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- OOM killer activity
- Unexpected process crashes
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "general protection fault")🔗 References
- https://access.redhat.com/errata/RHSA-2024:2394
- https://access.redhat.com/security/cve/CVE-2023-6531
- https://bugzilla.redhat.com/show_bug.cgi?id=2253034
- https://lore.kernel.org/all/c716c88321939156909cfa1bd8b0faaf1c804103.1701868795.git.asml.silence@gmail.com/
- http://packetstormsecurity.com/files/176533/Linux-Broken-Unix-GC-Interaction-Use-After-Free.html
- https://access.redhat.com/errata/RHSA-2024:2394
- https://access.redhat.com/security/cve/CVE-2023-6531
- https://bugzilla.redhat.com/show_bug.cgi?id=2253034
- https://lists.debian.org/debian-lts-announce/2024/01/msg00005.html
- https://lore.kernel.org/all/c716c88321939156909cfa1bd8b0faaf1c804103.1701868795.git.asml.silence@gmail.com/
