CVE-2023-53620
📋 TL;DR
A race condition in the Linux kernel's md (multiple device) driver can cause a soft lockup when displaying RAID resync progress. The vulnerability allows local attackers to trigger a denial of service by causing the kernel to enter an infinite loop. This affects systems using Linux software RAID (md) with resync operations.
💻 Affected Systems
- Linux kernel
⚠️ Risk & Real-World Impact
Worst Case
Complete system unresponsiveness requiring hard reboot, potentially causing data corruption or service disruption.
Likely Case
Local denial of service affecting the specific system where the vulnerability is triggered, requiring reboot to restore functionality.
If Mitigated
Minimal impact with proper kernel patching and monitoring for system lockups.
🎯 Exploit Status
Requires local access and ability to trigger specific race condition during RAID resync operations. Not trivial to exploit reliably.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees via git commits: 23309704e90859af2662bedc44101e6d1d2ece7e, 6efddf1e32e2a264694766ca485a4f5e04ee82a7, b4acb6c3ede88d6b7d33742a09e63cfce5e7fb69
Vendor Advisory: https://git.kernel.org/stable/c/23309704e90859af2662bedc44101e6d1d2ece7e
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix. 2. Check with your distribution for specific kernel updates. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable md resync monitoring
linuxPrevent the vulnerable status_resync function from being triggered by disabling resync progress monitoring
echo 0 > /sys/block/mdX/md/sync_action
Note: Replace mdX with your actual md device
Avoid concurrent resync operations
linuxSchedule RAID resync operations during maintenance windows to minimize concurrent access
🧯 If You Can't Patch
- Monitor systems for soft lockups and have reboot procedures ready
- Restrict local user access to systems with md RAID arrays
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if using md RAID: cat /proc/mdstat and check kernel version with uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check if git commit containing fix is present in kernel source📡 Detection & Monitoring
Log Indicators:
- Kernel soft lockup messages in dmesg or /var/log/kern.log
- System becoming unresponsive with high CPU in kernel space
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND "soft lockup" AND "md"