CVE-2016-4536 in OpenAFS
Summary
by MITRE
The client in OpenAFS before 1.6.17 does not properly initialize the (1) AFSStoreStatus, (2) AFSStoreVolumeStatus, (3) VldbListByAttributes, and (4) ListAddrByAttributes structures, which might allow remote attackers to obtain sensitive memory information by leveraging access to RPC call traffic.
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Analysis
by VulDB Data Team • 11/26/2018
The vulnerability identified as CVE-2016-4536 affects the OpenAFS distributed file system implementation and represents a critical information disclosure flaw that stems from improper initialization of several key data structures within the client-side component. This vulnerability specifically impacts versions of OpenAFS prior to 1.6.17 and exposes sensitive memory contents to remote attackers who can intercept RPC call traffic. The affected structures include AFSStoreStatus, AFSStoreVolumeStatus, VldbListByAttributes, and ListAddrByAttributes, all of which are critical components in the file system's operation and communication protocols.
The technical flaw manifests when these data structures are not properly initialized before being populated with data from remote procedure calls. This improper initialization creates memory regions that contain residual data from previous operations or system states, effectively leaking sensitive information that should remain private. When RPC traffic is intercepted, attackers can analyze the unitialized memory segments to extract confidential data such as authentication tokens, session information, or other sensitive system details that were previously stored in those memory locations. This represents a classic case of information leakage through uninitialized memory access patterns that violates fundamental security principles of data isolation and confidentiality.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked memory contents could potentially contain authentication credentials, cryptographic keys, or other sensitive data that would allow attackers to escalate their privileges or gain unauthorized access to the distributed file system. The vulnerability is particularly concerning because it requires only network-level access to exploit, making it accessible to attackers who can intercept RPC traffic between client and server components. This aligns with the ATT&CK framework's information gathering and credential access techniques, where adversaries leverage network reconnaissance to extract sensitive data from memory structures.
From a compliance and security standards perspective, this vulnerability directly relates to CWE-248, which addresses improper initialization of variables, and represents a failure to implement proper memory management practices. The vulnerability also aligns with the principle of least privilege as defined in various security frameworks, since the improper initialization allows for unauthorized information disclosure that violates the system's security boundaries. Organizations using OpenAFS should prioritize immediate patching to version 1.6.17 or later, as the vulnerability provides attackers with a straightforward method to extract sensitive information from memory without requiring elevated privileges or complex exploitation techniques.
The remediation approach focuses on ensuring proper initialization of all affected data structures before they are populated with data from RPC calls. This requires code-level changes to guarantee that memory regions are properly cleared or initialized before data is written to them, preventing the leakage of residual information. Additionally, network segmentation and encryption of RPC traffic can provide additional defense-in-depth measures to limit the impact of such vulnerabilities. Security monitoring should include detection of anomalous RPC traffic patterns that might indicate exploitation attempts, while access controls and authentication mechanisms should be strengthened to limit the potential damage from any successful information disclosure attacks.