CVE-2023-53478
📋 TL;DR
A race condition vulnerability in the Linux kernel's tracing subsystem allows concurrent access to the 'last_cmd' variable, leading to use-after-free or double-free conditions. This affects Linux systems where synthetic events tracing is enabled and multiple users can access the synthetic_events node simultaneously. The vulnerability requires local access to the system.
💻 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
Kernel panic or system crash leading to denial of service, with potential for privilege escalation if combined with other vulnerabilities.
Likely Case
System instability, kernel crashes, or denial of service when multiple users concurrently manipulate synthetic events.
If Mitigated
Minimal impact if proper access controls restrict /sys/kernel/tracing access to privileged users only.
🎯 Exploit Status
Proof-of-concept scripts are provided in the CVE description. Exploitation requires local access and appropriate permissions to write to synthetic_events.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 4ccf11c4e8a8e051499d53a12f502196c97a758e, 8826d9e7bd51e7656f78baa4472e8e2f5e7069f0, or 9fe183f659a2704255e5d84f6ae308c234a113ec
Vendor Advisory: https://git.kernel.org/stable/c/4ccf11c4e8a8e051499d53a12f502196c97a758e
Restart Required: Yes
Instructions:
1. Update to a patched kernel version from your distribution vendor. 2. Reboot the system to load the new kernel. 3. Verify the fix by checking kernel version or testing the PoC scripts.
🔧 Temporary Workarounds
Restrict synthetic_events access
linuxLimit write access to /sys/kernel/tracing/synthetic_events to root only
chmod 600 /sys/kernel/tracing/synthetic_events
chown root:root /sys/kernel/tracing/synthetic_events
Disable synthetic events
linuxRemove synthetic events support from kernel if not needed
echo 0 > /sys/kernel/tracing/events/synthetic/enable
🧯 If You Can't Patch
- Implement strict access controls on /sys/kernel/tracing directory
- Monitor system logs for kernel panic or crash events related to tracing
🔍 How to Verify
Check if Vulnerable:
Check if kernel version is vulnerable by comparing with distribution security advisories. Test with provided PoC scripts if safe testing environment exists.Check Version:
uname -rVerify Fix Applied:
Check kernel version contains the fix commits. Test with PoC scripts to ensure no crashes occur.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN reports for double-free or use-after-free in tracing subsystem
- System crash/reboot events
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("double-free" OR "use-after-free") AND "tracing"