CVE-2022-0168 in Linux
Summary
by MITRE • 08/26/2022
A denial of service (DOS) issue was found in the Linux kernel’s smb2_ioctl_query_info function in the fs/cifs/smb2ops.c Common Internet File System (CIFS) due to an incorrect return from the memdup_user function. This flaw allows a local, privileged (CAP_SYS_ADMIN) attacker to crash the system.
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Analysis
by VulDB Data Team • 05/18/2025
The vulnerability identified as CVE-2022-0168 represents a critical denial of service flaw within the Linux kernel's implementation of the Common Internet File System protocol. This issue specifically affects the smb2_ioctl_query_info function located in the fs/cifs/smb2ops.c file, which handles information queries for SMB2 protocol operations. The vulnerability stems from an improper handling of memory allocation and data copying operations within the kernel's CIFS subsystem, creating a condition that can be exploited to cause system instability and complete system crashes.
The technical root cause of this vulnerability lies in the incorrect return handling from the memdup_user function, which is responsible for duplicating user-space memory into kernel space. When the memdup_user function fails to properly validate or process memory operations, it can return invalid or corrupted data pointers that subsequently propagate through the smb2_ioctl_query_info function. This flaw is particularly dangerous because it operates within the kernel's file system operations, where errors can cascade into system-wide failures. The vulnerability specifically requires a local attacker with CAP_SYS_ADMIN capabilities, which represents a privileged user context that can execute system-level operations.
The operational impact of CVE-2022-0168 extends beyond simple system crashes, as it can lead to complete system downtime and potential data loss. Attackers with sufficient privileges can leverage this vulnerability to cause sustained denial of service conditions that may require system reboots to resolve. The flaw affects systems running Linux kernels that implement SMB2 protocol support through the CIFS module, making it particularly concerning for enterprise environments that rely heavily on file sharing and network storage solutions. This vulnerability aligns with CWE-248, which addresses "Uncaught Exception" conditions in software systems, and represents a specific instance where improper exception handling in kernel space leads to system instability.
Mitigation strategies for CVE-2022-0168 primarily focus on applying the appropriate kernel security patches released by the Linux kernel development team. System administrators should prioritize updating their kernel versions to include fixes that address the memory handling issues in the memdup_user function and related SMB2 operations. Additionally, organizations should implement privilege separation measures and ensure that only trusted users have CAP_SYS_ADMIN capabilities, as this privilege level is required to exploit the vulnerability. Network segmentation and monitoring solutions can help detect anomalous behavior that might indicate exploitation attempts. The vulnerability also connects to ATT&CK technique T1499.004, which covers "Endpoint Denial of Service" through kernel-level attacks, highlighting the need for comprehensive endpoint protection strategies that include kernel-level monitoring and defense mechanisms.