CVE-2024-36971
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's networking subsystem where __dst_negative_advice() improperly handles RCU rules when clearing socket destination cache entries. This allows attackers to potentially crash systems or execute arbitrary code by exploiting race conditions in UDP socket handling. All Linux systems using affected kernel versions are vulnerable.
💻 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 memory corruption leading to arbitrary code execution with kernel privileges, resulting in complete system compromise.
Likely Case
Kernel panic or system crash causing denial of service, potentially leading to privilege escalation in sophisticated attacks.
If Mitigated
Limited impact with proper network segmentation and minimal UDP services exposed.
🎯 Exploit Status
Exploitation requires UDP socket access and precise timing to trigger the race condition.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with fixes from the provided git commit hashes
Vendor Advisory: https://git.kernel.org/stable/c/051c0bde9f0450a2ec3d62a86d2a0d2fad117f13
Restart Required: Yes
Instructions:
1. Check current kernel version with 'uname -r'. 2. Update kernel using distribution's package manager (apt/yum/dnf). 3. Reboot system to load patched kernel. 4. Verify fix with 'uname -r' and check against patched versions.
🔧 Temporary Workarounds
Disable unnecessary UDP services
linuxReduce attack surface by disabling UDP services not required for system operation
systemctl stop [udp-service]
systemctl disable [udp-service]
Network segmentation
linuxRestrict UDP traffic to trusted networks only using firewall rules
iptables -A INPUT -p udp -s [trusted-network] -j ACCEPT
iptables -A INPUT -p udp -j DROP
🧯 If You Can't Patch
- Implement strict network access controls to limit UDP traffic to essential services only
- Monitor systems for kernel crashes or unusual UDP socket activity
🔍 How to Verify
Check if Vulnerable:
Check kernel version against affected ranges and verify if system uses UDP sockets extensivelyCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated to include the fix commits: 051c0bde9f0450a2ec3d62a86d2a0d2fad117f13 or other listed commits📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Unexpected system crashes
- High UDP socket creation/destruction rates
Network Indicators:
- Unusual UDP traffic patterns to kernel-exposed services
- Multiple UDP connection attempts with timing patterns
SIEM Query:
source="kernel" AND ("panic" OR "oops") OR (protocol="UDP" AND rate_threshold>1000)🔗 References
- https://git.kernel.org/stable/c/051c0bde9f0450a2ec3d62a86d2a0d2fad117f13
- https://git.kernel.org/stable/c/2295a7ef5c8c49241bff769e7826ef2582e532a6
- https://git.kernel.org/stable/c/5af198c387128a9d2ddd620b0f0803564a4d4508
- https://git.kernel.org/stable/c/81dd3c82a456b0015461754be7cb2693991421b4
- https://git.kernel.org/stable/c/92f1655aa2b2294d0b49925f3b875a634bd3b59e
- https://git.kernel.org/stable/c/b8af8e6118a6605f0e495a58d591ca94a85a50fc
- https://git.kernel.org/stable/c/db0082825037794c5dba9959c9de13ca34cc5e72
- https://git.kernel.org/stable/c/eacb8b195579c174a6d3e12a9690b206eb7f28cf
- https://git.kernel.org/stable/c/051c0bde9f0450a2ec3d62a86d2a0d2fad117f13
- https://git.kernel.org/stable/c/2295a7ef5c8c49241bff769e7826ef2582e532a6
- https://git.kernel.org/stable/c/5af198c387128a9d2ddd620b0f0803564a4d4508
- https://git.kernel.org/stable/c/81dd3c82a456b0015461754be7cb2693991421b4
- https://git.kernel.org/stable/c/92f1655aa2b2294d0b49925f3b875a634bd3b59e
- https://git.kernel.org/stable/c/b8af8e6118a6605f0e495a58d591ca94a85a50fc
- https://git.kernel.org/stable/c/db0082825037794c5dba9959c9de13ca34cc5e72
- https://git.kernel.org/stable/c/eacb8b195579c174a6d3e12a9690b206eb7f28cf
- https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-36971
