CVE-2023-53476
📋 TL;DR
A NULL pointer dereference vulnerability exists in the Linux kernel's iw_cxgb4 driver, which handles Chelsio T4/T5/T6 RDMA hardware. This vulnerability could cause kernel panics or system crashes when specific conditions occur during RDMA connection management. Systems using Chelsio RDMA hardware with vulnerable kernel versions are affected.
💻 Affected Systems
- Linux kernel with iw_cxgb4 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, potentially causing data loss or service disruption.
Likely Case
System crash or kernel panic when specific RDMA operations are performed, resulting in denial of service.
If Mitigated
No impact if the vulnerable driver is not loaded or RDMA functionality is not used.
🎯 Exploit Status
Requires ability to trigger specific RDMA operations; likely requires local access or RDMA network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commits 24278dc380aab6a1aef0a75317f57ad4c2453cf6, 4ca446b127c568b59cb8d9748b6f70499624bb18, 76e0396313c79ecd0df44ee3c18745cfac52b3e6, or dd55240e4364d64befcc575b0d33091881524f42
Vendor Advisory: https://git.kernel.org/stable/c/24278dc380aab6a1aef0a75317f57ad4c2453cf6
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify iw_cxgb4 driver is updated.
🔧 Temporary Workarounds
Disable iw_cxgb4 driver
linuxPrevent loading of vulnerable driver if Chelsio RDMA functionality is not required
echo 'blacklist iw_cxgb4' >> /etc/modprobe.d/blacklist.conf
rmmod iw_cxgb4
🧯 If You Can't Patch
- Disable RDMA functionality if not required
- Restrict access to systems using Chelsio RDMA hardware
🔍 How to Verify
Check if Vulnerable:
Check if iw_cxgb4 module is loaded: lsmod | grep iw_cxgb4. Check kernel version: uname -r and compare with patched versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and iw_cxgb4 module loads without errors in dmesg.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/messages or dmesg
- NULL pointer dereference errors mentioning iw_cxgb4 or c4iw_fill_res_cm_id_entry
Network Indicators:
- Unexpected RDMA connection failures
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "kernel panic") AND ("iw_cxgb4" OR "c4iw")