CVE-2023-53565
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's Broadcom FullMAC wireless driver (brcmfmac) can cause system crashes when resuming from suspend or during manual driver binding. This affects Linux systems using Broadcom WiFi chipsets. The vulnerability allows local attackers to cause denial of service.
💻 Affected Systems
- Linux kernel with brcmfmac 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 and system crash requiring hard reboot, potentially causing data loss or corruption.
Likely Case
WiFi functionality stops working after system resume from suspend, requiring driver reload or reboot.
If Mitigated
Minor service disruption with automatic driver recovery mechanisms.
🎯 Exploit Status
Exploitation requires local access and can be triggered by normal system operations like resume from suspend.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 60fc756fc8e6954a5618eecac73b255d651602e4 and 84766e77a5c35e2b60e34f570c62fc97adc05e09
Vendor Advisory: https://git.kernel.org/stable/c/60fc756fc8e6954a5618eecac73b255d651602e4
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Reboot system to load patched kernel. 3. Verify driver functionality after resume from suspend.
🔧 Temporary Workarounds
Disable WiFi suspend/resume
linuxPrevent system from entering suspend mode where WiFi driver would need to resume.
sudo systemctl mask sleep.target suspend.target hibernate.target hybrid-sleep.target
Unload and reload driver
linuxManually reload driver after resume if crash occurs.
sudo modprobe -r brcmfmac
sudo modprobe brcmfmac
🧯 If You Can't Patch
- Avoid system suspend/resume cycles on affected devices
- Use alternative WiFi hardware or USB WiFi adapters
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if brcmfmac driver is loaded: lsmod | grep brcmfmacCheck Version:
uname -rVerify Fix Applied:
Test system resume from suspend and verify WiFi remains functional📡 Detection & Monitoring
Log Indicators:
- Kernel NULL pointer dereference messages
- brcmfmac driver crash logs
- System crash/panic logs after resume
Network Indicators:
- Sudden WiFi disconnection after system resume
SIEM Query:
kernel: *NULL pointer dereference* AND brcmfmac OR kernel: BUG: *brcmf_pcie_probe*