CVE-2023-53222
📋 TL;DR
A Linux kernel vulnerability in the JFS filesystem allows local attackers to cause a kernel crash (denial of service) through a shift-out-of-bounds error. This affects systems using JFS filesystem with unvalidated db_l2nbperpage values during mount. The vulnerability requires local access to trigger.
💻 Affected Systems
- Linux kernel with JFS 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 →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
Kernel panic leading to system crash and denial of service, potentially causing data corruption or loss if filesystem operations are interrupted.
Likely Case
Local denial of service through kernel crash when mounting specially crafted JFS filesystems or during filesystem operations.
If Mitigated
Minimal impact if JFS filesystem is not used or proper validation is implemented.
🎯 Exploit Status
Requires local access and ability to mount JFS filesystems. Syzbot found this through fuzzing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel stable releases containing commits: 11509910c599cbd04585ec35a6d5e1a0053d84c1, 2a03c4e683d33d17b667418eb717b13dda1fac6b, 47b7eaae08e8b2f25bdf37bc14d21be090bcb20f, 8c1efe3f74a7864461b0dff281c5562154b4aa8e, a4855aeb13e4ad1f23e16753b68212e180f7d848
Vendor Advisory: https://git.kernel.org/stable/c/11509910c599cbd04585ec35a6d5e1a0053d84c1
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable JFS filesystem
linuxPrevent loading of JFS kernel module to eliminate attack surface
echo 'install jfs /bin/false' >> /etc/modprobe.d/disable-jfs.conf
rmmod jfs 2>/dev/null || true
Restrict JFS mounting
linuxLimit which users can mount filesystems
chmod 700 /bin/mount
chmod 700 /sbin/mount.jfs
🧯 If You Can't Patch
- Avoid using JFS filesystem for any storage
- Implement strict access controls to prevent unauthorized users from mounting filesystems
🔍 How to Verify
Check if Vulnerable:
Check if JFS module is loaded: lsmod | grep jfs. If loaded and kernel version is unpatched, system is vulnerable.Check Version:
uname -rVerify Fix Applied:
Check kernel version against patched releases from your distribution. Verify JFS operations work without crashes.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- JFS mount failures or crashes
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "jfs" AND "crash")🔗 References
- https://git.kernel.org/stable/c/11509910c599cbd04585ec35a6d5e1a0053d84c1
- https://git.kernel.org/stable/c/2a03c4e683d33d17b667418eb717b13dda1fac6b
- https://git.kernel.org/stable/c/47b7eaae08e8b2f25bdf37bc14d21be090bcb20f
- https://git.kernel.org/stable/c/8c1efe3f74a7864461b0dff281c5562154b4aa8e
- https://git.kernel.org/stable/c/a4855aeb13e4ad1f23e16753b68212e180f7d848
- https://git.kernel.org/stable/c/c7feb54b113802d2aba98708769d3c33fb017254
- https://git.kernel.org/stable/c/de984faecddb900fa850af4df574a25b32bb93f5
- https://git.kernel.org/stable/c/ef5c205b6e6f8d1f18ef0b4a9832b1b5fa85f7f2
