CVE-2024-27394
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's TCP Authentication Option (TCP-AO) implementation. Attackers could potentially exploit this to cause kernel crashes or execute arbitrary code, affecting all Linux systems using TCP-AO functionality. The vulnerability occurs during TCP connection establishment when cryptographic keys are improperly managed.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash, or potential arbitrary code execution with kernel privileges resulting in complete system compromise.
Likely Case
System instability, kernel crashes, or denial of service affecting TCP connections using authentication options.
If Mitigated
Minimal impact if TCP-AO is not enabled or systems are patched; isolated crashes in affected TCP connections.
🎯 Exploit Status
Exploitation requires TCP-AO to be configured and used, which limits attack surface. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check kernel git commits: 80e679b352c3ce5158f3f778cfb77eb767e586fb and ca4fb6c6764b3f75b4f5aa81db1536291897ff7f
Vendor Advisory: https://git.kernel.org/stable/c/80e679b352c3ce5158f3f778cfb77eb767e586fb
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable TCP-AO
linuxDisable TCP Authentication Option functionality if not required
sysctl -w net.ipv4.tcp_ao=0
sysctl -w net.ipv6.tcp_ao=0
🧯 If You Can't Patch
- Disable TCP Authentication Option using sysctl commands
- Implement network segmentation to limit exposure of systems using TCP-AO
🔍 How to Verify
Check if Vulnerable:
Check if TCP-AO is enabled: sysctl net.ipv4.tcp_ao net.ipv6.tcp_ao. If enabled and kernel is unpatched, system is vulnerable.Check Version:
uname -rVerify Fix Applied:
Check kernel version against patched versions from distribution vendor. Verify TCP-AO functionality works without crashes.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- TCP connection failures with authentication
- System crashes during TCP handshake
Network Indicators:
- Unusual TCP connection attempts with authentication options
- Failed TCP-AO handshakes
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "TCP-AO")