CVE-2023-52842
📋 TL;DR
This CVE describes an uninitialized memory vulnerability in the Linux kernel's virtio/vsock subsystem. An attacker could exploit this to read uninitialized kernel memory, potentially leaking sensitive information. Systems using virtio-vsock with affected Linux kernel versions are vulnerable.
💻 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
Kernel memory information disclosure leading to privilege escalation or system compromise through subsequent attacks.
Likely Case
Information disclosure of uninitialized kernel memory, potentially exposing sensitive data like pointers or other kernel structures.
If Mitigated
Minimal impact with proper kernel hardening and isolation of virtio-vsock usage.
🎯 Exploit Status
The provided reproducer demonstrates triggering the uninitialized memory access, but full exploitation for information disclosure requires additional steps. Exploitation requires ability to create vsock connections.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check kernel version with commits: 0b8906fb48b99e993d6e8a12539f618f4854dd26, 34c4effacfc329aeca5635a69fd9e0f6c90b4101, cd12535b97dd7d18cf655ec78ce1cf1f29a576be
Vendor Advisory: https://git.kernel.org/stable/c/0b8906fb48b99e993d6e8a12539f618f4854dd26
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable virtio/vsock
linuxRemove or disable virtio_vsock kernel module if not required.
sudo rmmod virtio_vsock
echo 'blacklist virtio_vsock' | sudo tee /etc/modprobe.d/blacklist-virtio-vsock.conf
🧯 If You Can't Patch
- Restrict vsock socket creation using capabilities or SELinux/AppArmor policies.
- Isolate virtualization guests and limit their access to host resources.
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if virtio_vsock module is loaded: lsmod | grep virtio_vsockCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits: sudo grep -r '0b8906fb48b99e993d6e8a12539f618f4854dd26\|34c4effacfc329aeca5635a69fd9e0f6c90b4101\|cd12535b97dd7d18cf655ec78ce1cf1f29a576be' /boot/config-*📡 Detection & Monitoring
Log Indicators:
- Kernel logs showing KMSAN or similar sanitizer reports for virtio_transport_recv_pkt
- Unexpected vsock connection attempts
Network Indicators:
- Unusual vsock traffic patterns
SIEM Query:
Process monitoring for vsock socket creation or kernel module loading events related to virtio_vsock.🔗 References
- https://git.kernel.org/stable/c/0b8906fb48b99e993d6e8a12539f618f4854dd26
- https://git.kernel.org/stable/c/34c4effacfc329aeca5635a69fd9e0f6c90b4101
- https://git.kernel.org/stable/c/cd12535b97dd7d18cf655ec78ce1cf1f29a576be
- https://git.kernel.org/stable/c/0b8906fb48b99e993d6e8a12539f618f4854dd26
- https://git.kernel.org/stable/c/34c4effacfc329aeca5635a69fd9e0f6c90b4101
- https://git.kernel.org/stable/c/cd12535b97dd7d18cf655ec78ce1cf1f29a576be
