CVE-2022-49369
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's AMT (Automatic Multicast Tunneling) module. When the amt_rcv() function receives packets but cannot find the corresponding socket, it fails to free the received socket buffer (skb), leading to potential memory exhaustion. This affects Linux systems with AMT functionality enabled.
💻 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 →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
Sustained exploitation could lead to kernel memory exhaustion, causing system instability, denial of service, or potential kernel crashes.
Likely Case
Memory leak gradually consumes kernel memory, potentially leading to performance degradation or system instability over time.
If Mitigated
With proper monitoring and memory limits, impact is limited to potential performance issues rather than complete system failure.
🎯 Exploit Status
Exploitation requires sending specially crafted packets to AMT interfaces. No public exploits are known, but the vulnerability is relatively straightforward to trigger.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in stable kernel versions via commits: 1a1a0e80e005, 4b8032d39b27, 60d9c020c699
Vendor Advisory: https://git.kernel.org/stable/c/1a1a0e80e005cbdc2c250fc858e1d8570f4e4acb
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Check if AMT module is loaded (lsmod | grep amt). 3. If loaded, reboot system to load patched kernel. 4. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable AMT module
linuxUnload the AMT kernel module if not required
sudo rmmod amt
Prevent AMT module loading
linuxBlacklist AMT module to prevent loading
echo 'blacklist amt' | sudo tee /etc/modprobe.d/blacklist-amt.conf
🧯 If You Can't Patch
- Disable AMT functionality if not required
- Implement network segmentation to restrict access to AMT interfaces
🔍 How to Verify
Check if Vulnerable:
Check if AMT module is loaded: 'lsmod | grep amt'. If loaded, check kernel version against patched versions.Check Version:
uname -rVerify Fix Applied:
After patching, verify AMT module still functions correctly and monitor kernel memory usage for leaks.📡 Detection & Monitoring
Log Indicators:
- Kernel oom-killer events
- Abnormal memory consumption in /proc/meminfo
- System instability logs
Network Indicators:
- Unusual traffic to AMT ports (typically UDP 2268)
- High packet rates to AMT interfaces
SIEM Query:
source="kernel" AND ("oom" OR "out of memory") AND process="amt"