CVE-2016-9772 in OpenAFS
Summary
by MITRE
OpenAFS 1.6.19 and earlier allows remote attackers to obtain sensitive directory information via vectors involving the (1) client cache partition, (2) fileserver vice partition, or (3) certain RPC responses.
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Analysis
by VulDB Data Team • 08/11/2020
The vulnerability identified as CVE-2016-9772 affects OpenAFS versions 1.6.19 and earlier, representing a significant security flaw in the distributed file system implementation. This issue resides in the way OpenAFS handles directory information exposure across multiple system components including client cache partitions, fileserver vice partitions, and specific rpc responses. The vulnerability stems from insufficient access controls and information disclosure mechanisms that allow remote attackers to gather sensitive directory data without proper authentication or authorization. The flaw specifically targets the internal partitioning mechanisms that separate different functional areas of the file system, creating potential attack vectors through improperly protected data flows.
The technical implementation of this vulnerability involves the improper handling of directory metadata within OpenAFS's distributed architecture. When clients interact with the fileserver or process rpc responses, the system fails to adequately validate access permissions for directory information. This allows attackers to exploit the partitioning structure to gain unauthorized visibility into directory hierarchies, file locations, and potentially sensitive metadata about the file system structure. The vulnerability affects the core functionality of OpenAFS's security model, particularly in how it manages data isolation between different system partitions including the client cache and vice partitions that handle file operations.
From an operational perspective, this vulnerability poses substantial risk to organizations relying on OpenAFS for distributed file storage and access control. Remote attackers could leverage this flaw to map the entire directory structure of affected systems, potentially identifying sensitive files, understanding system layout, and planning more sophisticated attacks. The impact extends beyond simple information disclosure as it could enable attackers to identify system weaknesses, understand file access patterns, and potentially facilitate further exploitation attempts. This vulnerability directly violates the principle of least privilege and could compromise the confidentiality of directory structures that should remain protected within the system's security boundaries.
The vulnerability aligns with CWE-200, which addresses information exposure, and represents a classic case of insufficient access control in distributed systems. It also maps to several ATT&CK techniques including T1083 (File and Directory Discovery) and T1069 (Permission Groups) as attackers could use this information to understand system permissions and file structures. Organizations should immediately implement mitigations including upgrading to OpenAFS versions 1.6.20 or later where this vulnerability has been addressed through improved access controls and enhanced validation of directory information flows. Additional protective measures include network segmentation, implementing proper firewall rules to limit rpc traffic, and monitoring for unusual directory access patterns that might indicate exploitation attempts. Regular security audits of distributed file system configurations should be conducted to ensure proper partitioning and access control mechanisms remain intact.