CVE-2023-1670
📋 TL;DR
A use-after-free vulnerability in the Linux kernel's Xircom 16-bit PCMCIA Ethernet driver allows local users to crash the system or potentially escalate privileges. This affects systems with the vulnerable driver loaded, typically older hardware or specialized embedded systems. Attackers need local access to exploit this flaw.
💻 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 privilege escalation to root, allowing complete system compromise and persistence.
Likely Case
Kernel panic leading to system crash and denial of service.
If Mitigated
No impact if driver is not loaded or system is patched.
🎯 Exploit Status
Exploit requires local access and knowledge of kernel exploitation techniques. Proof-of-concept code is available in the kernel mailing list references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel 6.3-rc1 and later
Vendor Advisory: https://lore.kernel.org/all/20230316161526.1568982-1-zyytlz.wz%40163.com/
Restart Required: Yes
Instructions:
1. Update Linux kernel to version 6.3-rc1 or later. 2. For distributions with backported patches, apply security updates. 3. Reboot system to load patched kernel.
🔧 Temporary Workarounds
Unload vulnerable driver
linuxPrevent exploitation by unloading the Xircom PCMCIA driver if not needed
sudo rmmod xirc2ps_cs
Blacklist driver module
linuxPrevent driver from loading at boot
echo 'blacklist xirc2ps_cs' | sudo tee /etc/modprobe.d/blacklist-xirc2ps.conf
sudo update-initramfs -u
🧯 If You Can't Patch
- Unload the xirc2ps_cs kernel module if not required for system functionality
- Implement strict access controls to limit local user privileges and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check if xirc2ps_cs module is loaded: lsmod | grep xirc2ps_cs. If loaded and kernel version < 6.3-rc1, system is vulnerable.Check Version:
uname -rVerify Fix Applied:
Verify kernel version is >= 6.3-rc1 or check that xirc2ps_cs module is not loaded: uname -r && lsmod | grep xirc2ps_cs📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages related to xirc2ps_cs driver
- Unexpected system crashes/reboots
- Failed module loading attempts
Network Indicators:
- None - local exploitation only
SIEM Query:
source="kernel" AND ("xirc2ps_cs" OR "use-after-free" OR "general protection fault")🔗 References
- https://lists.debian.org/debian-lts-announce/2023/05/msg00005.html
- https://lists.debian.org/debian-lts-announce/2023/05/msg00006.html
- https://lore.kernel.org/all/20230316161526.1568982-1-zyytlz.wz%40163.com/
- https://security.netapp.com/advisory/ntap-20230526-0010/
- https://lists.debian.org/debian-lts-announce/2023/05/msg00005.html
- https://lists.debian.org/debian-lts-announce/2023/05/msg00006.html
- https://lore.kernel.org/all/20230316161526.1568982-1-zyytlz.wz%40163.com/
- https://security.netapp.com/advisory/ntap-20230526-0010/
