CVE-2023-53647
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's Hyper-V VMBus driver allows local attackers to cause a kernel panic (system crash) by triggering an ACPI namespace lookup failure. This affects Linux systems running as guests on Hyper-V or KVM/QEMU virtualization platforms with VMBus enabled. The vulnerability is triggered during boot when the system attempts to locate Hyper-V MMIO ranges.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Local attacker causes kernel panic leading to denial of service, requiring system reboot to restore functionality.
Likely Case
System crashes during boot on affected virtualization platforms, preventing the system from starting properly.
If Mitigated
With proper patching, no impact - the lookup is properly terminated at the ACPI root object.
🎯 Exploit Status
Exploitation requires local access and ability to influence ACPI namespace lookup. The vulnerability manifests as a boot-time crash on affected virtualization platforms.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel branches (commits: 64f09d45e94547fbf219f36d1d02ac42742c028c, 78e04bbff849b51b56f5925b1945db2c6e128b61, 96db43aced395844a7abc9a0a5cc702513e3534a, 9fc162c59edc841032a3553eb2334320abab0784)
Vendor Advisory: https://git.kernel.org/stable/c/64f09d45e94547fbf219f36d1d02ac42742c028c
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable VMBus/Hyper-V PV interface
allPrevent the vulnerable code path from being executed by disabling Hyper-V paravirtualization interface
Add 'nohyperv' to kernel boot parameters in GRUB configuration
🧯 If You Can't Patch
- Avoid using affected virtualization platforms (Hyper-V, KVM/QEMU with VMBus)
- Ensure systems are not exposed to local attackers who could trigger the vulnerability
🔍 How to Verify
Check if Vulnerable:
Check if system crashes during boot when running as guest on Hyper-V or KVM/QEMU with VMBus enabled. Review kernel logs for ACPI-related NULL pointer dereference errors.Check Version:
uname -rVerify Fix Applied:
Check kernel version against patched versions. Test boot process on affected virtualization platforms without crashes.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages during boot
- ACPI namespace lookup errors
- NULL pointer dereference in acpi_ns_lookup or related functions
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for kernel panic events or ACPI error messages in system logs during boot sequence