CVE-2023-53523
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's gs_usb CAN bus driver allows denial of service when specific race conditions occur during driver unloading/reloading. This affects systems using gs_usb devices (like candlelight firmware) for CAN bus communication, potentially causing kernel crashes or system instability.
💻 Affected Systems
- Linux kernel with gs_usb driver
📦 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
Kernel panic leading to system crash and denial of service, requiring physical or remote reboot.
Likely Case
System instability or crash when gs_usb driver is unloaded/reloaded while CAN bus traffic is active.
If Mitigated
No impact if proper patching is applied or gs_usb driver is not used.
🎯 Exploit Status
Exploitation requires specific timing and hardware conditions; not trivial but possible with local access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 210a8cffc9c1b044281c0a868485c870c9c11374 and 5886e4d5ecec3e22844efed90b2dd383ef804b3a applied
Vendor Advisory: https://git.kernel.org/stable/c/210a8cffc9c1b044281c0a868485c870c9c11374
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Reboot system to load patched kernel. 3. Verify gs_usb driver loads without errors.
🔧 Temporary Workarounds
Unload gs_usb driver
linuxPrevent vulnerability by not using gs_usb CAN interfaces
sudo rmmod gs_usb
Blacklist gs_usb module
linuxPrevent gs_usb driver from loading automatically
echo 'blacklist gs_usb' | sudo tee /etc/modprobe.d/blacklist-gs_usb.conf
sudo update-initramfs -u
🧯 If You Can't Patch
- Avoid unloading/reloading gs_usb driver while CAN bus is active
- Use alternative CAN interface hardware not requiring gs_usb driver
🔍 How to Verify
Check if Vulnerable:
Check if gs_usb module is loaded: lsmod | grep gs_usbCheck Version:
uname -rVerify Fix Applied:
Check kernel version includes fix commits or test by unloading/reloading gs_usb with active CAN traffic📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- NULL pointer dereference errors in dmesg
- gs_usb driver crash logs
Network Indicators:
- CAN bus communication interruptions
SIEM Query:
search 'kernel: BUG: unable to handle kernel NULL pointer dereference' AND 'gs_usb'