CVE-2023-6932
📋 TL;DR
This CVE-2023-6932 is a use-after-free vulnerability in the Linux kernel's IGMP (Internet Group Management Protocol) component that allows local attackers to escalate privileges. The race condition enables a timer to be registered on a freed object, leading to memory corruption. Systems running vulnerable Linux kernel versions with IGMP functionality are affected.
💻 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
Local attacker gains root privileges, leading to complete system compromise, data theft, and persistent backdoor installation.
Likely Case
Local user escalates to root privileges, enabling unauthorized access to sensitive data and system resources.
If Mitigated
Attack limited to local users; systems with strict access controls and minimal local user accounts have reduced exposure.
🎯 Exploit Status
Requires local access and race condition triggering; no public exploit code identified in references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions including commit e2b706c691905fe78468c361aaabc719d0a496f1
Vendor Advisory: https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html
Restart Required: Yes
Instructions:
1. Update kernel package using distribution's package manager. 2. For Debian: apt update && apt upgrade linux-image-*. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable IGMP functionality
linuxDisable IGMP protocol to prevent exploitation (may break multicast networking)
echo 0 > /proc/sys/net/ipv4/igmp_max_memberships
sysctl -w net.ipv4.igmp_max_memberships=0
🧯 If You Can't Patch
- Restrict local user access to essential personnel only
- Implement strict SELinux/AppArmor policies to limit kernel access
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched commit: uname -r && git log --oneline | grep e2b706c691905fe78468c361aaabc719d0a496f1Check Version:
uname -rVerify Fix Applied:
Verify kernel includes the fix commit: grep e2b706c691905fe78468c361aaabc719d0a496f1 /boot/config-$(uname -r) or check kernel source📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- OOM killer activity
- Unusual privilege escalation in audit logs
Network Indicators:
- Unusual IGMP traffic patterns from local users
SIEM Query:
source="kernel" AND ("panic" OR "use-after-free" OR "igmp")🔗 References
- http://packetstormsecurity.com/files/177029/Kernel-Live-Patch-Security-Notice-LSN-0100-1.html
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=e2b706c691905fe78468c361aaabc719d0a496f1
- https://kernel.dance/e2b706c691905fe78468c361aaabc719d0a496f1
- https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html
- https://lists.debian.org/debian-lts-announce/2024/01/msg00005.html
- http://packetstormsecurity.com/files/177029/Kernel-Live-Patch-Security-Notice-LSN-0100-1.html
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=e2b706c691905fe78468c361aaabc719d0a496f1
- https://kernel.dance/e2b706c691905fe78468c361aaabc719d0a496f1
- https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html
- https://lists.debian.org/debian-lts-announce/2024/01/msg00005.html
