CVE-2023-53623
📋 TL;DR
A race condition in the Linux kernel's memory swap subsystem allows concurrent swapoff and get_swap_pages() operations to cause memory corruption. This vulnerability can lead to kernel panics and system crashes, affecting Linux systems running kernel versions after stable 5.10.y.
💻 Affected Systems
- Linux kernel
⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, potentially causing data loss or corruption in active swap operations.
Likely Case
System instability, warning messages in kernel logs, and potential crashes during heavy swap operations.
If Mitigated
Minor performance impact from proper locking, but no security or stability issues.
🎯 Exploit Status
Exploitation requires local access and ability to trigger concurrent swap operations. The vulnerability was discovered through stress testing rather than malicious exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in kernel commits: 111a79d9b92f0a679fe300ccd3119ae9741f3d54, 4bdf1514b4268d29360ba9e43becdd49955bc7ae, 6fe7d6b992113719e96744d974212df3fcddc76c, 85cc118ce6f1a627901b6db50c9d01f2ad78cdbf, a55f268abdb74ac5633b75a09fefb58458e9d2a2
Vendor Advisory: https://git.kernel.org/stable/c/111a79d9b92f0a679fe300ccd3119ae9741f3d54
Restart Required: Yes
Instructions:
1. Update Linux kernel to a version containing the fix. 2. Check with your distribution vendor for specific patched kernel packages. 3. Reboot the system after kernel update.
🔧 Temporary Workarounds
Disable swap
linuxTemporarily disable swap functionality to prevent the race condition
swapoff -a
Limit swap operations
linuxRestrict user ability to perform swap operations
chmod 600 /proc/sys/vm/swappiness
sysctl -w vm.swappiness=0
🧯 If You Can't Patch
- Monitor system logs for swap-related warnings and kernel panics
- Avoid running concurrent swap-intensive operations like stress-ng-swap or madvise(MADV_PAGEOUT)
🔍 How to Verify
Check if Vulnerable:
Check kernel version: uname -r and compare against affected versions (after 5.10.y). Check if swap is enabled: swapon --showCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the fix commits. Check dmesg for absence of plist_check_prev_next_node warnings during swap operations.📡 Detection & Monitoring
Log Indicators:
- Kernel warnings containing 'plist_check_prev_next_node'
- Swap-related error messages in dmesg
- System crash/panic logs
Network Indicators:
- None - this is a local kernel vulnerability
SIEM Query:
source="kernel" AND ("plist_check_prev_next_node" OR "swap" AND "panic" OR "WARNING")🔗 References
- https://git.kernel.org/stable/c/111a79d9b92f0a679fe300ccd3119ae9741f3d54
- https://git.kernel.org/stable/c/4bdf1514b4268d29360ba9e43becdd49955bc7ae
- https://git.kernel.org/stable/c/6fe7d6b992113719e96744d974212df3fcddc76c
- https://git.kernel.org/stable/c/85cc118ce6f1a627901b6db50c9d01f2ad78cdbf
- https://git.kernel.org/stable/c/a55f268abdb74ac5633b75a09fefb58458e9d2a2
- https://git.kernel.org/stable/c/b9927d3a60ca9ed35625470888629c074e687ba0
- https://git.kernel.org/stable/c/e7bba7ddb4318d5ea939c8db747c2c2780ab66f4
- https://git.kernel.org/stable/c/ea8c42b3b6d95ced3a4f555f04686d00ef0bb206
