CVE-2022-49727
📋 TL;DR
This CVE describes an integer overflow vulnerability in the Linux kernel's IPv6 L2TP implementation. When sending L2TP over IPv6 packets, improper bounds checking allows an attacker to trigger a signed integer overflow, potentially causing kernel crashes or other undefined behavior. This affects any Linux system using L2TP over IPv6 networking.
💻 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 →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 →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 enabling further exploitation through memory corruption.
Likely Case
System crash or kernel panic resulting in denial of service, requiring system reboot to restore functionality.
If Mitigated
Minimal impact if L2TP over IPv6 is not used or properly firewalled.
🎯 Exploit Status
Exploitation requires sending specially crafted L2TP over IPv6 packets to a vulnerable system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check kernel git commits for specific fixed versions
Vendor Advisory: https://git.kernel.org/stable/c/034246122f5c5e2e2a0b9fe04e24517920e9beb1
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable L2TP over IPv6
linuxPrevent exploitation by disabling L2TP over IPv6 functionality
echo 'net.ipv6.conf.all.disable_ipv6 = 1' >> /etc/sysctl.conf
sysctl -p
Firewall L2TP traffic
linuxBlock L2TP over IPv6 at network perimeter
iptables -A INPUT -p udp --dport 1701 -j DROP
ip6tables -A INPUT -p udp --dport 1701 -j DROP
🧯 If You Can't Patch
- Implement network segmentation to isolate systems using L2TP over IPv6
- Deploy network monitoring to detect exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare against patched versions in git commitsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version matches patched version and test L2TP over IPv6 functionality📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/messages or dmesg
- Unexpected system reboots
Network Indicators:
- Unusual L2TP over IPv6 traffic patterns
- Multiple connection attempts to UDP port 1701
SIEM Query:
source="kernel" AND ("panic" OR "Oops") AND process="l2tp_ip6"🔗 References
- https://git.kernel.org/stable/c/034246122f5c5e2e2a0b9fe04e24517920e9beb1
- https://git.kernel.org/stable/c/0e818d433fc2718fe4da044ffca7431812a7e04e
- https://git.kernel.org/stable/c/27a37755ceb401111ded76810359d3adc4b268a1
- https://git.kernel.org/stable/c/2cf73c7cb6125083408d77f43d0e84d86aed0000
- https://git.kernel.org/stable/c/2f42389d270f2304c8855b0b63498a5a4d0c053d
- https://git.kernel.org/stable/c/6c4e3486d21173d60925ef52e512cae727b43d30
- https://git.kernel.org/stable/c/b8879ca1fd7348b4d5db7db86dcb97f60c73d751
- https://git.kernel.org/stable/c/f638a84afef3dfe10554c51820c16e39a278c915
