CVE-2023-53403
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's time/debug subsystem where debugfs_lookup() is called without proper cleanup. The vulnerability allows attackers to gradually exhaust kernel memory over time, potentially leading to system instability or denial of service. All Linux systems using affected kernel versions are potentially vulnerable.
💻 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
Sustained exploitation could lead to kernel memory exhaustion, causing system crashes, denial of service, or unpredictable system behavior that might enable privilege escalation in combination with other vulnerabilities.
Likely Case
Gradual memory leak leading to system performance degradation over time, potentially requiring system reboots to restore normal operation.
If Mitigated
Minimal impact with proper monitoring and memory management controls in place; system remains stable with occasional performance issues.
🎯 Exploit Status
Exploitation requires local access and knowledge of debugfs interface; memory leak is gradual rather than immediate.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commits: 15cffd01ed80e3506e29ba9f441e2358413b7317, 5b268d8abaec6cbd4bd70d062e769098d96670aa, b588b42d077ce93c98704b41003bcec6a564b738, dc39fbd865a9819db4b622f610ba17b2ebc294f4
Vendor Advisory: https://git.kernel.org/stable/c/15cffd01ed80e3506e29ba9f441e2358413b7317
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 debugfs access
allPrevent access to debugfs interface to block potential exploitation
umount /sys/kernel/debug
echo 'debugfs /sys/kernel/debug debugfs defaults,noauto 0 0' >> /etc/fstab
🧯 If You Can't Patch
- Restrict debugfs access to privileged users only using filesystem permissions
- Implement monitoring for unusual memory consumption patterns and system performance degradation
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions from kernel git commitsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version after update matches patched version and monitor system memory usage for stability📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- System logs showing memory pressure warnings
- Process crashes related to memory allocation failures
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for: 'kernel: Out of memory' OR 'kernel: allocation failure' OR system logs showing repeated debugfs access