CVE-2023-53008
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's CIFS (Common Internet File System) implementation. When reconnecting or mounting CIFS shares, the system fails to properly free authentication key response memory before reallocating it, potentially causing gradual memory exhaustion. This affects any Linux system using CIFS/SMB file sharing.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Sustained exploitation could lead to kernel memory exhaustion, causing system instability, denial of service, or kernel crashes on affected systems.
Likely Case
Gradual memory consumption over time during CIFS reconnect/mount operations, potentially leading to performance degradation or service disruption.
If Mitigated
Minimal impact with proper monitoring and memory limits; systems may experience temporary performance issues during heavy CIFS operations.
🎯 Exploit Status
Exploitation requires ability to trigger CIFS reconnect/mount operations. This is a reliability issue rather than a security bypass.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commits 2fe58d977ee05da5bb89ef5dc4f5bf2dc15db46f and 893d45394dbe4b5cbf3723c19e2ccc8b93a6ac9b
Vendor Advisory: https://git.kernel.org/stable/c/2fe58d977ee05da5bb89ef5dc4f5bf2dc15db46f
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 matches patched release.
🔧 Temporary Workarounds
Disable CIFS module
linuxPrevent loading of CIFS kernel module if not required
echo 'install cifs /bin/false' >> /etc/modprobe.d/disable-cifs.conf
rmmod cifs
Use alternative file sharing
linuxReplace CIFS with NFS or other file sharing protocols
🧯 If You Can't Patch
- Monitor system memory usage and CIFS processes closely
- Implement memory limits for processes using CIFS
- Restrict CIFS usage to non-critical systems
- Schedule regular system reboots to clear memory
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if CIFS module is loaded: lsmod | grep cifs && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits and test CIFS reconnect operations while monitoring memory📡 Detection & Monitoring
Log Indicators:
- Kernel oom-killer messages
- Memory allocation failures in kernel logs
- CIFS reconnect errors
Network Indicators:
- Increased CIFS/SMB reconnect attempts
- Unusual file share disconnections
SIEM Query:
source="kernel" AND ("oom" OR "memory" OR "cifs") AND ("allocation failed" OR "reconnect")