CVE-2022-2991 in Linux
Summary
by MITRE • 08/25/2022
A heap-based buffer overflow was found in the Linux kernel's LightNVM subsystem. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length heap-based buffer. This vulnerability allows a local attacker to escalate privileges and execute arbitrary code in the context of the kernel. The attacker must first obtain the ability to execute high-privileged code on the target system to exploit this vulnerability.
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Analysis
by VulDB Data Team • 10/01/2022
The heap-based buffer overflow vulnerability in the Linux kernel's LightNVM subsystem represents a critical security flaw that demonstrates the dangers of inadequate input validation in kernel space operations. This vulnerability resides within the LightNVM subsystem which provides support for non-volatile memory devices and is designed to handle user-space interactions with storage hardware. The flaw manifests when user-supplied data is copied to a fixed-length heap-based buffer without proper validation of the data length, creating a classic buffer overflow condition that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from improper bounds checking within kernel memory management functions. When the LightNVM subsystem processes user input for device configuration or data transfer operations, it fails to validate the length of incoming data before performing memory copy operations into pre-allocated heap buffers. This oversight creates a situation where an attacker can provide data exceeding the buffer capacity, leading to memory corruption that can be leveraged for privilege escalation. The vulnerability specifically affects the kernel's handling of user-space data structures that are passed through the LightNVM interface, making it particularly dangerous for systems that utilize NVMe over Fabrics or other non-volatile memory technologies.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass full system compromise capabilities. A local attacker who can execute code on the target system gains the ability to leverage this flaw for kernel-level code execution, effectively bypassing all user-mode security controls. The exploitation process requires the attacker to first establish a foothold on the system, after which they can manipulate the LightNVM subsystem to trigger the buffer overflow condition. This vulnerability directly maps to CWE-121 heap-based buffer overflow and aligns with ATT&CK technique T1068, which covers local privilege escalation through kernel exploits. The attack surface is particularly concerning for enterprise environments where kernel-level access can provide complete control over system resources and data.
Mitigation strategies for this vulnerability must address both immediate patching requirements and long-term architectural improvements. The primary remediation involves applying the official kernel patches that implement proper input validation and bounds checking for all user-supplied data within the LightNVM subsystem. Organizations should prioritize patch deployment across all affected kernel versions, particularly those running Linux kernel versions 5.15 and earlier where this vulnerability was identified. Additional protective measures include disabling the LightNVM subsystem entirely if it is not required for system operations, implementing kernel module blacklisting for non-essential storage drivers, and monitoring for unusual kernel memory access patterns that might indicate exploitation attempts. System administrators should also consider implementing runtime protections such as kernel address space layout randomization and stack canaries to make exploitation more difficult, though these measures provide only partial defense against sophisticated attacks. The vulnerability highlights the importance of robust input validation practices in kernel space code development and serves as a reminder of the critical need for comprehensive security testing of storage subsystems that interact with user-space applications.