CVE-2023-53449
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's s390/dasd driver. If exploited, it could cause gradual memory exhaustion on affected systems, potentially leading to system instability or denial of service. This affects Linux systems running on IBM s390/zSeries architecture with DASD storage devices.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Sustained exploitation could lead to complete system memory exhaustion, causing kernel panics, system crashes, or denial of service requiring physical intervention.
Likely Case
Gradual memory consumption over time leading to system performance degradation, application failures, or eventual system instability requiring reboot.
If Mitigated
With proper monitoring and memory limits, impact is limited to performance degradation that can be detected and addressed before system failure.
🎯 Exploit Status
Exploitation requires local access and ability to trigger the specific error path in dasd_eckd_init(). This is a reliability issue rather than a security bypass.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commits 460e9bed82e49db1b823dcb4e421783854d86c40 and related fixes
Vendor Advisory: https://git.kernel.org/stable/c/460e9bed82e49db1b823dcb4e421783854d86c40
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. For RHEL/SUSE: Use vendor-provided kernel updates. 3. For custom kernels: Apply the git commits listed in references. 4. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable DASD driver if not needed
linuxIf DASD storage is not required, prevent loading of the vulnerable driver module
echo 'blacklist dasd_eckd_mod' >> /etc/modprobe.d/blacklist-dasd.conf
rmmod dasd_eckd_mod
🧯 If You Can't Patch
- Implement strict memory monitoring and alerting for s390 systems
- Restrict local access to s390 systems with DASD storage to trusted users only
🔍 How to Verify
Check if Vulnerable:
Check kernel version and architecture: uname -r && uname -m. If s390 architecture and using DASD, check if kernel version includes the fix commits.Check Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check that the dasd driver functions properly without memory leaks using system monitoring tools.📡 Detection & Monitoring
Log Indicators:
- Kernel oom-killer messages
- System memory exhaustion warnings
- DASD driver error messages in dmesg
Network Indicators:
- None - this is a local memory management issue
SIEM Query:
Search for kernel logs containing 'Out of memory' or 'dasd' errors on s390 systems🔗 References
- https://git.kernel.org/stable/c/460e9bed82e49db1b823dcb4e421783854d86c40
- https://git.kernel.org/stable/c/544a552be0869231799784279d52704c4d314d33
- https://git.kernel.org/stable/c/a50e28d433acf22258f9f34831057387f04ef074
- https://git.kernel.org/stable/c/aede5230d154b6b237985ec9df7ebbd1dce96810
- https://git.kernel.org/stable/c/ee986d80acdef710a886be404308188ea11000c8
- https://git.kernel.org/stable/c/ef3a7ffc0a6f833578bc8d1dcb79d0633c7e4ec3
