CVE-2023-2269 Overview
A denial of service vulnerability exists in the Linux Kernel Device Mapper-Multipathing sub-component due to a recursive locking scenario that results in a deadlock condition. The flaw is located in the table_clear function within drivers/md/dm-ioctl.c. A local attacker with elevated privileges can exploit this vulnerability to cause the system to become unresponsive, leading to service disruption.
Critical Impact
Local attackers with high privileges can trigger a deadlock condition in the Device Mapper subsystem, causing complete system unavailability and requiring a reboot to recover.
Affected Products
- Linux Kernel version 6.2
- Fedora 36, 37, and 38
- Debian Linux 10.0, 11.0, and 12.0
- NetApp H300S/H500S/H700S/H410S/H410C Firmware
Discovery Timeline
- April 25, 2023 - CVE-2023-2269 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2023-2269
Vulnerability Analysis
This vulnerability is classified under CWE-667 (Improper Locking) and CWE-413 (Improper Resource Locking). The flaw exists in the Device Mapper (DM) subsystem of the Linux kernel, specifically within the multipathing component that provides I/O failover and load balancing for block devices.
The vulnerability requires local access to the system and high privileges to exploit. While the attack complexity is low, the impact is limited to availability—there is no compromise of confidentiality or integrity. An attacker cannot read or modify data, but can effectively render the system unusable until a manual intervention (typically a reboot) is performed.
Root Cause
The root cause is a recursive locking condition in the table_clear function found in drivers/md/dm-ioctl.c. When certain operations are performed on Device Mapper tables, the code path can attempt to acquire a lock that is already held by the same thread, creating a deadlock scenario. This improper lock handling violates proper kernel locking semantics and results in the affected thread becoming permanently blocked.
Attack Vector
The attack vector is local, requiring the attacker to have authenticated access to the target system with elevated privileges. The attacker can trigger the vulnerability by issuing specific ioctl commands to the Device Mapper interface that cause the recursive locking condition.
The exploitation flow involves:
- Gaining local access with appropriate privileges to interact with /dev/mapper/ devices
- Initiating a table_clear operation through the DM ioctl interface
- Triggering the code path that leads to recursive lock acquisition
- The kernel thread deadlocks, causing system-wide service disruption
No exploit code is publicly available for this vulnerability. For technical discussion, refer to the Linux Kernel Mailing List Discussion.
Detection Methods for CVE-2023-2269
Indicators of Compromise
- System becomes unresponsive with no apparent CPU or memory exhaustion
- Processes interacting with Device Mapper devices hang indefinitely
- Kernel soft lockup warnings or hung task warnings in system logs
- Unable to perform block device operations involving dm-multipath
Detection Strategies
- Monitor kernel logs for soft lockup detection messages related to Device Mapper threads
- Implement watchdog mechanisms to detect system unresponsiveness
- Track ioctl system calls targeting /dev/mapper/control device
- Use SentinelOne Singularity platform to monitor for anomalous kernel behavior patterns
Monitoring Recommendations
- Enable kernel lockup detection (CONFIG_DETECT_HUNG_TASK, CONFIG_SOFTLOCKUP_DETECTOR)
- Configure appropriate timeout values for hung task detection
- Implement system health monitoring that can detect and alert on unresponsive states
- Deploy endpoint detection solutions capable of monitoring kernel-level activities
How to Mitigate CVE-2023-2269
Immediate Actions Required
- Update the Linux kernel to a patched version that addresses the recursive locking issue
- Apply vendor-specific patches from Debian, Fedora, or NetApp as applicable
- Restrict access to Device Mapper ioctl interfaces to trusted administrators only
- Implement monitoring to detect exploitation attempts before system becomes unresponsive
Patch Information
Security patches are available from multiple vendors. Refer to the following advisories for patched versions:
- Debian Security DSA-5448
- Debian Security DSA-5480
- Debian LTS Announce July 2023
- Debian LTS Announce October 2023
- Fedora Package Announcements
- NetApp Security Advisory NTAP-20230929-0004
Workarounds
- Limit access to Device Mapper control interfaces using file permissions
- Reduce the attack surface by disabling dm-multipath if not required in your environment
- Implement process isolation to limit which users can interact with kernel DM interfaces
- Use SELinux or AppArmor policies to restrict access to /dev/mapper/control
# Restrict Device Mapper control access to root only
chmod 600 /dev/mapper/control
# Verify Device Mapper multipath status
multipathd show config
# Check if dm-multipath module can be safely unloaded (if not needed)
lsmod | grep dm_multipath
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
