CVE-2023-35823
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's saa7134 media device driver. Attackers with local access can potentially exploit this to cause denial of service, escalate privileges, or execute arbitrary code. Systems running Linux kernels before version 6.3.2 with saa7134-based TV tuner/capture cards 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 →⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to root, arbitrary code execution, or complete system compromise
Likely Case
Kernel panic leading to denial of service or system crash
If Mitigated
Limited impact if proper access controls prevent local user access
🎯 Exploit Status
Requires local access and knowledge of driver interaction. No public exploits known as of analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel 6.3.2 and later
Vendor Advisory: https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.3.2
Restart Required: Yes
Instructions:
1. Update kernel to version 6.3.2 or later. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load patched kernel.
🔧 Temporary Workarounds
Disable saa7134 module
linuxPrevent loading of vulnerable driver module
echo 'blacklist saa7134' >> /etc/modprobe.d/blacklist.conf
rmmod saa7134
Restrict device access
linuxLimit access to saa7134 device files
chmod 600 /dev/saa7134*
chown root:root /dev/saa7134*
🧯 If You Can't Patch
- Implement strict access controls to prevent unauthorized local user access
- Monitor for kernel crashes or unusual driver behavior
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if saa7134 module is loaded: uname -r && lsmod | grep saa7134Check Version:
uname -rVerify Fix Applied:
Verify kernel version is 6.3.2+ and check saa7134 module status📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- System crashes/panics
- dmesg errors related to saa7134
Network Indicators:
- None - local exploit only
SIEM Query:
source="kernel" AND ("saa7134" OR "use-after-free" OR "general protection fault")🔗 References
- https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.3.2
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=30cf57da176cca80f11df0d9b7f71581fe601389
- https://lists.debian.org/debian-lts-announce/2023/07/msg00030.html
- https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html
- https://lore.kernel.org/all/49bb0b6a-e669-d4e7-d742-a19d2763e947%40xs4all.nl/
- https://lore.kernel.org/lkml/20230318085023.832510-1-zyytlz.wz%40163.com/t/
- https://security.netapp.com/advisory/ntap-20230803-0002/
- https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.3.2
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=30cf57da176cca80f11df0d9b7f71581fe601389
- https://lists.debian.org/debian-lts-announce/2023/07/msg00030.html
- https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html
- https://lore.kernel.org/all/49bb0b6a-e669-d4e7-d742-a19d2763e947%40xs4all.nl/
- https://lore.kernel.org/lkml/20230318085023.832510-1-zyytlz.wz%40163.com/t/
- https://security.netapp.com/advisory/ntap-20230803-0002/
