CVE-2024-53177
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's SMB client implementation. When open_cached_dir() encounters an error while parsing a lease from the server, it can free memory that is still being used by queued work, potentially leading to kernel crashes or privilege escalation. This affects Linux systems using the SMB client to access network shares.
💻 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
Local privilege escalation to root, kernel panic causing system crash, or remote code execution if combined with other vulnerabilities.
Likely Case
Kernel panic leading to system crash or denial of service, potentially causing data corruption or loss of access to SMB shares.
If Mitigated
System remains stable with no impact if the vulnerability is not triggered or patched.
🎯 Exploit Status
Exploitation requires triggering specific error paths in open_cached_dir() while a lease break is queued, making reliable exploitation challenging.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees via commits: 47655a12c6b1bca8fa230085eab2e85a076932b7, 791f833053578b9fd24252ebb7162a61bc3f805b, 97e2afcac0bebfef6a5360f4267ce4c44507b845, a9685b409a03b73d2980bbfa53eb47555802d0a9
Vendor Advisory: https://git.kernel.org/stable/c/47655a12c6b1bca8fa230085eab2e85a076932b7
Restart Required: Yes
Instructions:
1. Update to a patched kernel version from your distribution's repositories. 2. Reboot the system to load the new kernel. 3. Verify the kernel version after reboot.
🔧 Temporary Workarounds
Disable SMB client usage
linuxPrevent use of the vulnerable SMB client by avoiding SMB share access or using alternative protocols.
Mount SMB shares with nolease option
linuxMount SMB shares with the 'nolease' option to disable lease handling, which may prevent triggering the vulnerability.
mount -t cifs //server/share /mnt -o nolease
🧯 If You Can't Patch
- Restrict SMB share access to trusted users and systems only.
- Implement network segmentation to isolate systems using SMB client from critical infrastructure.
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if it includes the fix commits. Vulnerable if using an unpatched kernel with SMB client enabled.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the fix commits: 47655a12c6b1bca8fa230085eab2e85a076932b7, 791f833053578b9fd24252ebb7162a61bc3f805b, 97e2afcac0bebfef6a5360f4267ce4c44507b845, or a9685b409a03b73d2980bbfa53eb47555802d0a9.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- KASAN use-after-free reports in kernel logs
- System crashes during SMB operations
Network Indicators:
- Increased SMB error rates
- Failed SMB connection attempts followed by system instability
SIEM Query:
source="kernel" AND ("KASAN: slab-use-after-free" OR "BUG: KASAN" OR "smb2_cached_lease_break")