CVE-2023-52760
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's GFS2 filesystem quota handling. It allows attackers with local access to potentially crash the kernel or execute arbitrary code with kernel privileges. Systems using GFS2 filesystems are affected.
💻 Affected Systems
- Linux kernel with GFS2 filesystem support
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash or arbitrary code execution with kernel privileges, potentially resulting in full system compromise.
Likely Case
Kernel crash leading to denial of service and system instability.
If Mitigated
Limited to denial of service if kernel hardening features like KASLR and SMAP/SMEP are enabled.
🎯 Exploit Status
Requires local access and knowledge of GFS2 filesystem operations. Exploitation would require triggering specific filesystem operations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 08a28272faa750d4357ea2cb48d2baefd778ea81, bdcb8aa434c6d36b5c215d02a9ef07551be25a37, 7ad4e0a4f61c57c3ca291ee010a9d677d0199fba
Vendor Advisory: https://git.kernel.org/stable/c/08a28272faa750d4357ea2cb48d2baefd778ea81
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Check your distribution's security advisories for specific patched versions. 3. Reboot the system after kernel update.
🔧 Temporary Workarounds
Disable GFS2 filesystem
linuxRemove or disable GFS2 kernel module if not needed
modprobe -r gfs2
echo 'blacklist gfs2' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Restrict local user access to systems using GFS2 filesystems
- Implement strict access controls and monitor for unusual filesystem operations
🔍 How to Verify
Check if Vulnerable:
Check if GFS2 module is loaded: lsmod | grep gfs2. Check kernel version against patched versions from your distribution.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits. Check that GFS2 operations complete without kernel panics during filesystem unmount.📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages in /var/log/kern.log or dmesg
- System crashes during filesystem operations
- GFS2-related error messages
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("gfs2" OR "use-after-free" OR "slab")🔗 References
- https://git.kernel.org/stable/c/08a28272faa750d4357ea2cb48d2baefd778ea81
- https://git.kernel.org/stable/c/bdcb8aa434c6d36b5c215d02a9ef07551be25a37
- https://git.kernel.org/stable/c/08a28272faa750d4357ea2cb48d2baefd778ea81
- https://git.kernel.org/stable/c/7ad4e0a4f61c57c3ca291ee010a9d677d0199fba
- https://git.kernel.org/stable/c/bdcb8aa434c6d36b5c215d02a9ef07551be25a37
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
