CVE-2023-52438
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's binder driver that occurs during memory shrinker operations. It allows attackers to potentially crash the system or execute arbitrary code by exploiting race conditions between munmap() operations and shrinker callbacks. Systems running affected Linux kernel versions with binder enabled 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 →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
Kernel panic, system crash, or arbitrary code execution with kernel privileges leading to complete system compromise.
Likely Case
System instability, kernel crashes, or denial of service through memory corruption.
If Mitigated
Limited impact if binder is disabled or system has restricted user access to shrinker debug interfaces.
🎯 Exploit Status
Exploitation requires local access and ability to trigger shrinker operations through debug interfaces. The race condition makes timing critical for successful exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 3f489c2067c5824528212b0fc18b28d51332d906, 8ad4d580e8aff8de2a4d57c5930fcc29f1ffd4a6, 9fa04c93f24138747807fe75b5591bb680098f56, a49087ab93508b60d9b8add91707a22dda832869, a53e15e592b4dcc91c3a3b8514e484a0bdbc53a3
Vendor Advisory: https://git.kernel.org/stable/c/3f489c2067c5824528212b0fc18b28d51332d906
Restart Required: Yes
Instructions:
1. Update to a patched kernel version from your distribution vendor. 2. Rebuild kernel if using custom kernel with the fix commits. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable binder subsystem
linuxRemove or disable binder driver if not needed
modprobe -r binder
echo 'blacklist binder' >> /etc/modprobe.d/blacklist.conf
Restrict shrinker debug access
linuxLimit access to shrinker debug sysfs interface
chmod 600 /sys/kernel/debug/shrinker/*
mount -o remount,nosuid,nodev,noexec /sys/kernel/debug
🧯 If You Can't Patch
- Restrict user access to shrinker debug interfaces
- Implement strict privilege separation and limit local user capabilities
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if binder module is loaded: 'uname -r' and 'lsmod | grep binder'Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits or is newer than vulnerable versions. Check with distribution vendor for specific patched versions.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN reports of use-after-free in binder_alloc_free_page
- System crashes or instability
Network Indicators:
- None - local vulnerability
SIEM Query:
Search for kernel panic events or binder-related crash reports in system logs🔗 References
- https://git.kernel.org/stable/c/3f489c2067c5824528212b0fc18b28d51332d906
- https://git.kernel.org/stable/c/8ad4d580e8aff8de2a4d57c5930fcc29f1ffd4a6
- https://git.kernel.org/stable/c/9fa04c93f24138747807fe75b5591bb680098f56
- https://git.kernel.org/stable/c/a49087ab93508b60d9b8add91707a22dda832869
- https://git.kernel.org/stable/c/a53e15e592b4dcc91c3a3b8514e484a0bdbc53a3
- https://git.kernel.org/stable/c/c8c1158ffb007197f31f9d9170cf13e4f34cbb5c
- https://git.kernel.org/stable/c/e074686e993ff1be5f21b085a3b1b4275ccd5727
- https://git.kernel.org/stable/c/3f489c2067c5824528212b0fc18b28d51332d906
- https://git.kernel.org/stable/c/8ad4d580e8aff8de2a4d57c5930fcc29f1ffd4a6
- https://git.kernel.org/stable/c/9fa04c93f24138747807fe75b5591bb680098f56
- https://git.kernel.org/stable/c/a49087ab93508b60d9b8add91707a22dda832869
- https://git.kernel.org/stable/c/a53e15e592b4dcc91c3a3b8514e484a0bdbc53a3
- https://git.kernel.org/stable/c/c8c1158ffb007197f31f9d9170cf13e4f34cbb5c
- https://git.kernel.org/stable/c/e074686e993ff1be5f21b085a3b1b4275ccd5727
- https://lists.debian.org/debian-lts-announce/2024/06/msg00016.html
