CVE-2024-56621
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's UFS (Universal Flash Storage) driver allows local attackers to cause a kernel panic and system crash. This affects Linux systems using UFS storage devices when the driver module is removed. The vulnerability requires local access to trigger.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, potentially causing data corruption or loss if the system is performing critical operations.
Likely Case
System crash when UFS driver is unloaded, resulting in temporary denial of service until system reboot.
If Mitigated
No impact if the system doesn't use UFS storage or the driver isn't unloaded during normal operation.
🎯 Exploit Status
Requires local access and ability to trigger UFS driver removal. Not trivial to exploit in most environments.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in stable kernel versions via commits: 1695c4361d35b7bdadd7b34f99c9c07741e181e5, 2e7a3bb0331efb292e0fb022c36bc592137f0520, 57479e37d3f69efee2f0678568274db773284bc8
Vendor Advisory: https://git.kernel.org/stable/c/1695c4361d35b7bdadd7b34f99c9c07741e181e5
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
Prevent UFS driver unloading
linuxPrevent the ufshcd kernel module from being unloaded during system operation
echo 'install ufshcd /bin/false' >> /etc/modprobe.d/disable-ufshcd.conf
🧯 If You Can't Patch
- Restrict local user access to systems with UFS storage
- Avoid unloading UFS driver modules during normal operation
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if UFS driver is loaded: lsmod | grep ufshcdCheck Version:
uname -rVerify Fix Applied:
Check kernel version contains the fix commits or is newer than patched versions📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages mentioning 'NULL pointer dereference' and 'ufshcd_rtc_work' in dmesg or system logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND "NULL pointer dereference" AND "ufshcd"