CVE-2023-6176 in Linux
Summary
by MITRE • 11/16/2023
A null pointer dereference flaw was found in the Linux kernel API for the cryptographic algorithm scatterwalk functionality. This issue occurs when a user constructs a malicious packet with specific socket configuration, which could allow a local user to crash the system or escalate their privileges on the system.
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Analysis
by VulDB Data Team • 07/24/2025
The vulnerability identified as CVE-2023-6176 represents a critical null pointer dereference flaw within the Linux kernel's cryptographic scatterwalk API functionality. This issue resides in the kernel's handling of cryptographic operations and specifically affects the scatterwalk implementation that manages data transfer operations between user space and kernel space during cryptographic processing. The vulnerability stems from inadequate input validation and error handling within the kernel's cryptographic subsystem, particularly when processing malformed or specially crafted packets through socket configurations.
The technical flaw manifests when a local user constructs a malicious packet with specific socket parameters that trigger a null pointer dereference during the scatterwalk processing phase. This occurs because the kernel's cryptographic algorithm implementation fails to properly validate pointer references before dereferencing them during data transfer operations. The scatterwalk functionality is designed to handle data movement across multiple memory segments, but the absence of proper null checks creates an exploitable condition where a crafted packet can cause the kernel to attempt accessing a null memory address. This vulnerability is classified under CWE-476 as a null pointer dereference, which represents a fundamental memory safety issue in kernel space operations.
The operational impact of CVE-2023-6176 extends beyond simple system crashes to potentially enable privilege escalation attacks. When the null pointer dereference occurs, it typically results in a kernel panic or system crash that can be leveraged by malicious local users to disrupt system operations or potentially gain elevated privileges. The attack vector requires local access to the system, making it a local privilege escalation vulnerability rather than a remote one, but the implications remain severe as it allows attackers who already have user-level access to potentially elevate their privileges. The vulnerability affects systems running Linux kernel versions that include the affected cryptographic scatterwalk implementation, making it widespread across various distributions and deployment scenarios.
Mitigation strategies for CVE-2023-6176 primarily involve applying the latest kernel security patches released by the Linux kernel maintainers, which include proper null pointer validation and error handling in the scatterwalk cryptographic API. System administrators should prioritize updating their kernel versions to patched releases, particularly focusing on maintaining current security updates for production environments. Additionally, implementing kernel lockdown mechanisms and restricting local user access where possible can reduce the attack surface. Monitoring for suspicious system crashes or kernel panic events can help detect exploitation attempts, while maintaining proper system logging and audit trails provides forensic capabilities for post-incident analysis. Organizations should also consider implementing network segmentation and access control measures to limit local user access to critical systems, aligning with ATT&CK technique T1068 which addresses local privilege escalation through kernel vulnerabilities. The vulnerability demonstrates the importance of robust input validation in kernel space operations and highlights the need for comprehensive security testing of cryptographic implementations within operating system kernels.