CVE-2024-27070
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's F2FS filesystem driver that occurs during memory page fault handling. When exploited, it allows local attackers to potentially crash the system or execute arbitrary code with kernel privileges. Any system using the F2FS filesystem with an affected kernel version is 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 →⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to kernel-level access, system crash, or arbitrary code execution leading to complete system compromise.
Likely Case
Kernel panic or system crash causing denial of service, potentially leading to data corruption in F2FS filesystems.
If Mitigated
Limited to denial of service if kernel hardening features like KASAN or KPTI are enabled and prevent code execution.
🎯 Exploit Status
Requires local access and ability to trigger page faults on F2FS files. The vulnerability was discovered through syzkaller fuzzing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 8186e16a766d709a08f188d2f4e84098f364bea1, 897761d16564e899faecb9381b4818858705081f, eb70d5a6c932d9d23f4bb3e7b83782c21ac4b064
Vendor Advisory: https://git.kernel.org/stable/c/8186e16a766d709a08f188d2f4e84098f364bea1
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Check your distribution's security advisories for patched kernel packages. 3. Reboot the system after kernel update.
🔧 Temporary Workarounds
Disable F2FS filesystem
linuxPrevent use of F2FS filesystem to eliminate attack surface
# Remove F2FS module: rmmod f2fs
# Blacklist F2FS: echo 'blacklist f2fs' >> /etc/modprobe.d/blacklist.conf
Restrict user access
linuxLimit which users can access F2FS filesystems
# Use filesystem permissions and mount options to restrict access
🧯 If You Can't Patch
- Disable F2FS filesystem usage entirely
- Implement strict access controls and monitor for suspicious activity on F2FS filesystems
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if F2FS is loaded: uname -r && lsmod | grep f2fsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is patched and check git commit history for the fix commits📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN reports of use-after-free in f2fs_filemap_fault
- System crashes when accessing F2FS files
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for: 'KASAN: slab-use-after-free in f2fs_filemap_fault' OR 'kernel panic' with f2fs context🔗 References
- https://git.kernel.org/stable/c/8186e16a766d709a08f188d2f4e84098f364bea1
- https://git.kernel.org/stable/c/897761d16564e899faecb9381b4818858705081f
- https://git.kernel.org/stable/c/eb70d5a6c932d9d23f4bb3e7b83782c21ac4b064
- https://git.kernel.org/stable/c/8186e16a766d709a08f188d2f4e84098f364bea1
- https://git.kernel.org/stable/c/eb70d5a6c932d9d23f4bb3e7b83782c21ac4b064
