CVE-2023-53335
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's RDMA/cxgb4 driver could allow local attackers to cause a kernel panic (denial of service) or potentially execute arbitrary code. This affects systems using Chelsio T4/T5/T6 RDMA hardware with the vulnerable driver loaded. The vulnerability requires local access to the system.
💻 Affected Systems
- Linux kernel with cxgb4 RDMA 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 crash leading to system reboot, or potential privilege escalation if combined with other vulnerabilities to achieve arbitrary code execution in kernel context.
Likely Case
Local denial of service through kernel panic, requiring system reboot to restore functionality.
If Mitigated
Minimal impact if proper access controls prevent unauthorized local users from accessing RDMA functionality.
🎯 Exploit Status
Requires local access and ability to trigger the pass_establish() function through RDMA operations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 283861a4c52c1ea4df3dd1b6fc75a50796ce3524, 2cfc00e974d75a3aa8155f2660f57d342e1f67ca, 9dca64042d855a24b0bd81ce242e5dc7e939f6eb, 9ddc77eefb2a567b705c3c86ab2ddabe43cadf1b
Vendor Advisory: https://git.kernel.org/stable/c/283861a4c52c1ea4df3dd1b6fc75a50796ce3524
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Reboot system to load patched kernel. 3. Verify driver is functioning correctly post-update.
🔧 Temporary Workarounds
Unload cxgb4 RDMA driver
LinuxPrevent exploitation by unloading the vulnerable driver module if RDMA functionality is not required
sudo rmmod cxgb4
Blacklist driver module
LinuxPrevent automatic loading of the vulnerable driver
echo 'blacklist cxgb4' | sudo tee /etc/modprobe.d/blacklist-cxgb4.conf
🧯 If You Can't Patch
- Restrict local user access to systems with vulnerable driver
- Implement strict privilege separation to limit who can access RDMA functionality
🔍 How to Verify
Check if Vulnerable:
Check if cxgb4 module is loaded: lsmod | grep cxgb4 AND check kernel version against patched versionsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits and cxgb4 module loads without issues📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- NULL pointer dereference errors in kernel logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "kernel panic" OR "cxgb4")