CVE-2023-53343
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's IPv6 ICMP6 implementation allows local attackers to cause a kernel panic (denial of service) by sending specially crafted IPv6 packets with Segment Routing headers. This affects Linux systems with IPv6 enabled and certain IPv6 extension headers configured. The vulnerability requires local network access to exploit.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, potentially disrupting critical services.
Likely Case
Local denial of service attack causing temporary system unavailability until reboot.
If Mitigated
Minimal impact if proper network segmentation and access controls prevent local attackers from sending crafted packets.
🎯 Exploit Status
Exploitation requires local network access and ability to send raw IPv6 packets. The provided Python/Scapy script demonstrates the triggering condition but not full exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 1462e9d9aa52d14665eaca6d89d22c4af44ede04, 2aaa8a15de73874847d62eb595c6683bface80fd, 3fabca5d9cae0140b6aad09a1c6b9aa57089fbb8, 61b4c4659746959056450b92a5d7e6bc1243b31b, 8803c59fde4dd370a627dfbf7183682fa0cabf70
Vendor Advisory: https://git.kernel.org/stable/c/1462e9d9aa52d14665eaca6d89d22c4af44ede04
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Check your distribution's security advisories for specific patched versions. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable IPv6 Segment Routing
LinuxDisable Segment Routing (SRv6) and related IPv6 extension headers if not required.
echo 0 > /proc/sys/net/ipv6/conf/all/seg6_enabled
echo 0 > /proc/sys/net/ipv6/conf/default/seg6_enabled
Disable IPv6 entirely
LinuxIf IPv6 is not needed, disable it completely to mitigate this and other IPv6 vulnerabilities.
sysctl -w net.ipv6.conf.all.disable_ipv6=1
sysctl -w net.ipv6.conf.default.disable_ipv6=1
🧯 If You Can't Patch
- Implement strict network access controls to prevent unauthorized users from sending raw IPv6 packets
- Deploy network monitoring to detect and block suspicious IPv6 traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if IPv6 Segment Routing is enabled: cat /proc/sys/net/ipv6/conf/all/seg6_enabledCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is patched and test with the provided Python script to ensure no kernel panic occurs📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in system logs
- NULL pointer dereference errors in kernel logs
Network Indicators:
- Unusual IPv6 packets with link-local source/destination and Segment Routing headers
- Raw IPv6 packet transmission attempts
SIEM Query:
source="kernel" AND "NULL pointer dereference" AND "icmp6" OR source="kernel" AND "Oops" AND "icmp6_send"🔗 References
- https://git.kernel.org/stable/c/1462e9d9aa52d14665eaca6d89d22c4af44ede04
- https://git.kernel.org/stable/c/2aaa8a15de73874847d62eb595c6683bface80fd
- https://git.kernel.org/stable/c/3fabca5d9cae0140b6aad09a1c6b9aa57089fbb8
- https://git.kernel.org/stable/c/61b4c4659746959056450b92a5d7e6bc1243b31b
- https://git.kernel.org/stable/c/8803c59fde4dd370a627dfbf7183682fa0cabf70
- https://git.kernel.org/stable/c/aa657d319e6c7502a4eb85cc0ee80cc81b8e5724
- https://git.kernel.org/stable/c/d30ddd7ff15df9d91a793ce3f06f0190ff7afacc
