CVE-2023-28772
📋 TL;DR
A buffer overflow vulnerability in the Linux kernel's seq_buf_putmem_hex function allows local attackers to write beyond allocated memory boundaries. This affects Linux systems running kernel versions before 5.13.3. The vulnerability requires local access to exploit.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to root, kernel panic causing system crash, or arbitrary code execution in kernel context
Likely Case
Local denial of service through kernel panic or system instability
If Mitigated
Limited impact due to requirement for local access and specific kernel configurations
🎯 Exploit Status
Exploitation requires local access and knowledge of kernel memory layout. No public exploits have been reported.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel 5.13.3 and later
Vendor Advisory: https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.3
Restart Required: Yes
Instructions:
1. Update kernel to version 5.13.3 or later. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Restrict local access
linuxLimit local user access to systems running vulnerable kernels
Disable debugfs if not needed
linuxSome seq_buf usage occurs through debugfs; disabling it reduces attack surface
umount /sys/kernel/debug
echo 'debugfs /sys/kernel/debug debugfs noauto 0 0' >> /etc/fstab
🧯 If You Can't Patch
- Implement strict access controls to limit local user privileges
- Monitor systems for kernel panic events and unusual local user activity
🔍 How to Verify
Check if Vulnerable:
Check kernel version: uname -r. If version is earlier than 5.13.3, system is vulnerable.Check Version:
uname -rVerify Fix Applied:
After update, verify kernel version is 5.13.3 or later with: uname -r📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- Unexpected system reboots
- Segmentation faults in kernel-related processes
Network Indicators:
- No direct network indicators - local exploit only
SIEM Query:
source="kern.log" AND "kernel panic" OR "Oops" OR "segfault"🔗 References
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.3
- https://github.com/torvalds/linux/commit/d3b16034a24a112bb83aeb669ac5b9b01f744bb7
- https://lkml.kernel.org/r/20210626032156.47889-1-yun.zhou%40windriver.com
- https://lore.kernel.org/lkml/20210625122453.5e2fe304%40oasis.local.home/
- https://security.netapp.com/advisory/ntap-20230427-0005/
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.3
- https://github.com/torvalds/linux/commit/d3b16034a24a112bb83aeb669ac5b9b01f744bb7
- https://lkml.kernel.org/r/20210626032156.47889-1-yun.zhou%40windriver.com
- https://lore.kernel.org/lkml/20210625122453.5e2fe304%40oasis.local.home/
- https://security.netapp.com/advisory/ntap-20230427-0005/
