CVE-2022-48918
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's iwlwifi driver allows local attackers to cause a kernel panic (denial of service) when debugfs is disabled. This affects systems using Intel Wi-Fi hardware with the iwlwifi driver loaded. The vulnerability requires local access to trigger.
💻 Affected Systems
- Linux kernel iwlwifi driver (iwlmvm module)
📦 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 →🎯 Exploit Status
Exploitation requires local access and ability to load/unload kernel modules or trigger driver initialization with debugfs disabled.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 5a6248c0a22352f09ea041665d3bd3e18f6f872c, 7de1ed755e1ace30d97a724bad32452ed86b653b, fe51975ff13831e794e1bcd0039b305dcad3d7ba
Vendor Advisory: https://git.kernel.org/stable/c/5a6248c0a22352f09ea041665d3bd3e18f6f872c
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix. 2. Reboot system. 3. Verify kernel version with 'uname -r'.
🔧 Temporary Workarounds
Enable debugfs
linuxRemove 'debugfs=off' from kernel command line parameters
Edit /etc/default/grub or bootloader config, remove 'debugfs=off' from GRUB_CMDLINE_LINUX
Run 'update-grub' (Debian/Ubuntu) or 'grub2-mkconfig' (RHEL/Fedora)
Reboot
Blacklist iwlwifi module
linuxPrevent loading of vulnerable driver if Wi-Fi not needed
echo 'blacklist iwlwifi' >> /etc/modprobe.d/blacklist.conf
update-initramfs -u (or dracut --force)
Reboot
🧯 If You Can't Patch
- Ensure debugfs is enabled (default setting)
- Restrict local user access to systems with vulnerable configuration
🔍 How to Verify
Check if Vulnerable:
Check if 'debugfs=off' is in kernel cmdline: cat /proc/cmdline | grep debugfs=off AND check if iwlwifi module is loaded: lsmod | grep iwlwifiCheck Version:
uname -rVerify Fix Applied:
Check kernel version is patched: uname -r should show version after fix commits were merged📡 Detection & Monitoring
Log Indicators:
- Kernel panic/Oops messages mentioning iwl_mvm_dbgfs_register
- NULL pointer dereference at address 000000000000004f
- System crash/reboot events
Network Indicators:
- None - local vulnerability only
SIEM Query:
kernel: "BUG: kernel NULL pointer dereference" AND "iwl_mvm_dbgfs_register" OR "CR2: 000000000000004f"