CVE-2023-2156
📋 TL;DR
This vulnerability in the Linux kernel's RPL protocol handling allows unauthenticated remote attackers to trigger an assertion failure by sending specially crafted data. This causes a denial of service (system crash or hang) affecting systems with RPL protocol enabled. Any Linux system using RPL networking is potentially vulnerable.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Fedora by Fedoraproject
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
Complete system crash requiring manual reboot, potentially causing extended downtime for critical systems.
Likely Case
Kernel panic or system hang requiring reboot, disrupting services temporarily.
If Mitigated
No impact if RPL protocol is disabled or systems are patched.
🎯 Exploit Status
Exploitation requires sending specially crafted RPL packets to vulnerable systems with RPL enabled.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel patches available through distribution updates (check specific vendor advisories)
Vendor Advisory: https://bugzilla.redhat.com/show_bug.cgi?id=2196292
Restart Required: Yes
Instructions:
1. Check your Linux distribution's security advisories. 2. Apply kernel updates via package manager (yum update kernel / apt-get upgrade linux-image). 3. Reboot system to load patched kernel.
🔧 Temporary Workarounds
Disable RPL protocol
linuxDisable the RPL protocol if not needed
echo 0 > /proc/sys/net/ipv6/conf/all/rpl_seg_enabled
sysctl -w net.ipv6.conf.all.rpl_seg_enabled=0
🧯 If You Can't Patch
- Disable RPL protocol using sysctl commands
- Implement network filtering to block RPL protocol traffic (UDP port not standardized, typically uses IPv6 routing headers)
🔍 How to Verify
Check if Vulnerable:
Check if RPL is enabled: cat /proc/sys/net/ipv6/conf/all/rpl_seg_enabled (1 = enabled, 0 = disabled)Check Version:
uname -rVerify Fix Applied:
Check kernel version after update matches patched version from vendor advisory📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- System crash/reboot logs
- RPL protocol error messages in kernel logs
Network Indicators:
- Unusual RPL protocol traffic patterns
- Malformed IPv6 routing header packets
SIEM Query:
source="kernel" AND ("panic" OR "RPL" OR "assertion failure")🔗 References
- http://www.openwall.com/lists/oss-security/2023/05/17/8
- http://www.openwall.com/lists/oss-security/2023/05/17/9
- http://www.openwall.com/lists/oss-security/2023/05/18/1
- http://www.openwall.com/lists/oss-security/2023/05/19/1
- https://bugzilla.redhat.com/show_bug.cgi?id=2196292
- https://lists.debian.org/debian-lts-announce/2023/08/msg00001.html
- https://security.netapp.com/advisory/ntap-20230622-0001/
- https://www.debian.org/security/2023/dsa-5448
- https://www.debian.org/security/2023/dsa-5453
- https://www.zerodayinitiative.com/advisories/ZDI-23-547/
- http://www.openwall.com/lists/oss-security/2023/05/17/8
- http://www.openwall.com/lists/oss-security/2023/05/17/9
- http://www.openwall.com/lists/oss-security/2023/05/18/1
- http://www.openwall.com/lists/oss-security/2023/05/19/1
- https://bugzilla.redhat.com/show_bug.cgi?id=2196292
- https://lists.debian.org/debian-lts-announce/2023/08/msg00001.html
- https://security.netapp.com/advisory/ntap-20230622-0001/
- https://www.debian.org/security/2023/dsa-5448
- https://www.debian.org/security/2023/dsa-5453
- https://www.zerodayinitiative.com/advisories/ZDI-23-547/
