CVE-2023-1281
📋 TL;DR
A use-after-free vulnerability in the Linux kernel's traffic control index filter (tcindex) allows local attackers to escalate privileges to root. The flaw occurs when the imperfect hash area is updated during packet traversal, causing tcf_exts_exec() to reference freed memory. This affects Linux kernels from version 4.14 up to the fix commit.
💻 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 →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 full root privileges, enabling complete system compromise, data theft, persistence installation, and lateral movement.
Likely Case
Local user escalates to root privileges, gaining unauthorized administrative access to the system.
If Mitigated
With proper kernel hardening and least privilege enforcement, impact is limited to denial of service or partial privilege escalation.
🎯 Exploit Status
Exploitation requires local access and knowledge of kernel exploitation techniques. Public exploit details exist in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel with commit ee059170b1f7e94e55fa6cadee544e176a6e59c2 or later
Vendor Advisory: https://lists.debian.org/debian-lts-announce/2023/05/msg00005.html
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing fix commit ee059170b1f7e94e55fa6cadee544e176a6e59c2
2. For distributions: Use package manager (apt/yum/dnf) to update kernel package
3. Reboot system to load new kernel
🔧 Temporary Workarounds
Disable tcindex module
linuxPrevent loading of vulnerable tcindex kernel module
echo 'install tcindex /bin/false' >> /etc/modprobe.d/disable-tcindex.conf
rmmod tcindex
Restrict user access
allLimit local user access to prevent exploitation
Review and restrict user accounts with shell access
Implement least privilege principles
🧯 If You Can't Patch
- Implement strict access controls to limit local user accounts
- Monitor for privilege escalation attempts and kernel crashes
🔍 How to Verify
Check if Vulnerable:
Check kernel version: uname -r and verify if between 4.14 and pre-fix versions. Check if tcindex module is loaded: lsmod | grep tcindexCheck Version:
uname -rVerify Fix Applied:
Verify kernel includes fix commit: grep -q ee059170b1f7e94e55fa6cadee544e176a6e59c2 /proc/version_signature or check kernel source📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- Unexpected privilege escalation in audit logs
- System crashes related to tcindex
Network Indicators:
- None - local exploitation only
SIEM Query:
Search for: kernel panic, oops, or audit events showing uid changes from non-root to root🔗 References
- http://www.openwall.com/lists/oss-security/2023/04/11/3
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ee059170b1f7e94e55fa6cadee544e176a6e59c2
- https://kernel.dance/#ee059170b1f7e94e55fa6cadee544e176a6e59c2
- https://lists.debian.org/debian-lts-announce/2023/05/msg00005.html
- https://lists.debian.org/debian-lts-announce/2023/05/msg00006.html
- https://security.netapp.com/advisory/ntap-20230427-0004/
- http://www.openwall.com/lists/oss-security/2023/04/11/3
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ee059170b1f7e94e55fa6cadee544e176a6e59c2
- https://kernel.dance/#ee059170b1f7e94e55fa6cadee544e176a6e59c2
- https://lists.debian.org/debian-lts-announce/2023/05/msg00005.html
- https://lists.debian.org/debian-lts-announce/2023/05/msg00006.html
- https://security.netapp.com/advisory/ntap-20230427-0004/
