CVE-2024-56561
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's PCI endpoint controller subsystem. When destroying a PCI endpoint controller, the code incorrectly releases a PCI domain ID after freeing the device memory, potentially allowing attackers to execute arbitrary code or crash the system. This affects systems using PCI endpoint functionality in the Linux kernel.
💻 Affected Systems
- Linux kernel
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel memory corruption leading to arbitrary code execution with kernel privileges, system crash, or denial of service.
Likely Case
System instability, kernel panic, or denial of service affecting PCI endpoint functionality.
If Mitigated
Limited impact due to the specific nature of PCI endpoint controller usage and requirement for local access.
🎯 Exploit Status
Exploitation requires triggering pci_epc_destroy() with specific conditions. Likely requires local access or another vulnerability to trigger the code path.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 4acc902ed3743edd4ac2d3846604a99d17104359 or c74a1df6c2a2df7dd45c3fc1a5edc29a075dcf22
Vendor Advisory: https://git.kernel.org/stable/c/4acc902ed3743edd4ac2d3846604a99d17104359
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Check if your distribution has released security updates. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable PCI endpoint controller module
linuxPrevent loading of PCI endpoint controller module if not required
echo 'blacklist pci-epc' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Restrict access to systems using PCI endpoint functionality to trusted users only
- Implement strict privilege separation and limit users who can interact with PCI devices
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if pci_epc module is loaded: 'lsmod | grep pci_epc' and 'uname -r'Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits or is newer than patched version📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- PCI subsystem errors in dmesg
- System crashes related to PCI operations
Network Indicators:
- Not applicable - local vulnerability
SIEM Query:
Not applicable for network detection