CVE-2023-53402
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's printk subsystem when using debugfs_lookup() without proper cleanup. It affects Linux systems with debugfs enabled, potentially leading to kernel memory exhaustion over time. The vulnerability requires local access to exploit.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
An attacker with local access could repeatedly trigger the memory leak, causing kernel memory exhaustion and system instability or denial of service.
Likely Case
Accidental or repeated triggering by legitimate users could gradually consume kernel memory, potentially leading to system performance degradation or crashes over time.
If Mitigated
With proper access controls limiting debugfs access, the vulnerability has minimal impact as it requires local filesystem access to trigger.
🎯 Exploit Status
Exploitation requires local access to debugfs and knowledge of how to trigger the specific debugfs operations. No remote exploitation vector exists.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 13969236b6900b5a3625ad2193569588e978f1cc, 2e07fa2e30d48d24a791483774a3d4b76769e0cf, 55bf243c514553e907efcf2bda92ba090eca8c64, c578a68ffcdc2e8c72556bebdaae2b7500398e81
Vendor Advisory: https://git.kernel.org/stable/c/13969236b6900b5a3625ad2193569588e978f1cc
Restart Required: Yes
Instructions:
1. Update to a patched kernel version from your distribution vendor. 2. Reboot the system to load the new kernel. 3. Verify the fix by checking kernel version.
🔧 Temporary Workarounds
Disable debugfs access
allUnmount debugfs or restrict access to prevent exploitation
umount /sys/kernel/debug
mount -o remount,noexec,nosuid,nodev /sys/kernel/debug
Restrict debugfs permissions
allChange debugfs mount permissions to limit access
chmod 700 /sys/kernel/debug
chown root:root /sys/kernel/debug
🧯 If You Can't Patch
- Restrict access to debugfs filesystem to trusted users only
- Implement monitoring for unusual debugfs access patterns
🔍 How to Verify
Check if Vulnerable:
Check if debugfs is mounted and accessible: 'mount | grep debugfs' and 'ls -la /sys/kernel/debug'Check Version:
uname -rVerify Fix Applied:
Check kernel version against patched versions from your distribution vendor📡 Detection & Monitoring
Log Indicators:
- Kernel oom-killer messages
- System memory exhaustion warnings
- Repeated debugfs access in audit logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for: 'kernel: Out of memory' OR 'kernel: oom-killer' OR audit logs showing repeated debugfs access