CVE-2015-6587 in OpenAFS
Summary
by MITRE
The vlserver in OpenAFS before 1.6.13 allows remote authenticated users to cause a denial of service (out-of-bounds read and crash) via a crafted regular expression in a VL_ListAttributesN2 RPC.
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Analysis
by VulDB Data Team • 06/14/2022
The vulnerability identified as CVE-2015-6587 affects the vlserver component within OpenAFS version 1.6.12 and earlier, representing a critical security flaw that enables remote authenticated attackers to execute denial of service attacks through carefully crafted input. This vulnerability specifically targets the VL_ListAttributesN2 RPC call within the Volume Location service, which is responsible for managing volume location information in the OpenAFS distributed file system. The flaw manifests when the server processes regular expressions provided by authenticated users, creating a scenario where malformed input can trigger unexpected behavior in the underlying code execution.
The technical root cause of this vulnerability stems from inadequate input validation and bounds checking within the regular expression processing logic of the vlserver component. When a malicious user submits a specially crafted regular expression through the VL_ListAttributesN2 RPC interface, the server fails to properly validate the input boundaries before processing the pattern. This oversight leads to an out-of-bounds read condition where the program attempts to access memory locations beyond the allocated buffer boundaries, ultimately causing the server process to crash and terminate unexpectedly. The vulnerability is classified as a buffer over-read issue that directly violates the principles of secure memory management and input sanitization.
From an operational perspective, this vulnerability presents significant risks to OpenAFS deployments since it requires only authenticated access to exploit, meaning that any user with valid credentials can potentially disrupt the volume location service. The denial of service impact extends beyond simple service interruption as it can affect the entire distributed file system availability, potentially causing cascading failures across dependent services and applications that rely on OpenAFS for file storage and access. The vulnerability affects the core functionality of the volume location service, which is fundamental to OpenAFS operations, making it a critical target for exploitation in environments where high availability and continuous service delivery are essential.
The security implications of this vulnerability align with CWE-129, which addresses improper validation of array index or buffer bounds, and can be mapped to ATT&CK technique T1499.004 for network denial of service attacks. Organizations using OpenAFS versions prior to 1.6.13 face substantial risk as this vulnerability can be exploited to create persistent service disruptions that may require manual intervention to restore normal operations. The impact extends to business continuity and operational reliability, particularly in enterprise environments where OpenAFS serves as a foundational storage infrastructure component. Mitigation efforts should focus on immediate patch deployment to version 1.6.13 or later, which includes proper bounds checking and input validation mechanisms. Additionally, network segmentation and access controls should be implemented to limit the scope of potential exploitation, while monitoring systems should be configured to detect anomalous RPC activity patterns that may indicate attempted exploitation of this vulnerability.