CVE-2019-18603 in OpenAFS
Summary
by MITRE
OpenAFS before 1.6.24 and 1.8.x before 1.8.5 is prone to information leakage upon certain error conditions because uninitialized RPC output variables are sent over the network to a peer.
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Analysis
by VulDB Data Team • 01/29/2024
OpenAFS versions prior to 1.6.24 and 1.8.x versions before 1.8.5 contain a critical information disclosure vulnerability that arises from improper handling of RPC output variables during error conditions. This vulnerability falls under the CWE-248 category, which addresses "Uncaught Exception" scenarios where uninitialized variables may contain sensitive data from previous operations or memory contents. The flaw specifically occurs when RPC (Remote Procedure Call) responses are generated and transmitted over the network to peer systems, where uninitialized memory segments are inadvertently included in the output payload.
The technical implementation of this vulnerability stems from the RPC framework's handling of error states within the OpenAFS communication protocols. When certain error conditions are encountered during RPC processing, the system fails to properly initialize output variables before populating them with error data or response information. This results in the transmission of uninitialized memory contents, which may contain remnants of previous data, session information, or other sensitive material from the system's memory space. The vulnerability is particularly concerning because it operates at the network protocol level, making it accessible to any entity capable of intercepting RPC communications between OpenAFS servers and clients.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked data could potentially include authentication tokens, session identifiers, cryptographic keys, or other sensitive operational information. Attackers who can intercept RPC traffic between OpenAFS components can exploit this weakness to reconstruct portions of memory contents, potentially leading to credential compromise, session hijacking, or further exploitation opportunities. This vulnerability represents a significant risk to distributed systems relying on OpenAFS for file sharing and authentication services, as the information leakage can occur silently without alerting system administrators to the compromise.
Network-based attack vectors can leverage this vulnerability through passive network monitoring or active interception techniques, aligning with ATT&CK technique T1041 for Exfiltration Over C2 Channel and T1567 for Exfiltration Over Web Service. The attack surface is particularly broad given that OpenAFS implementations often involve multiple servers and clients communicating over various network protocols. Organizations should prioritize patching their OpenAFS installations to versions 1.6.24 or 1.8.5 and later, while also implementing network monitoring to detect potential exploitation attempts. Additional mitigations include implementing network segmentation to limit RPC communication exposure, deploying intrusion detection systems to monitor for unusual RPC traffic patterns, and conducting regular security assessments of distributed file systems to identify similar uninitialized variable vulnerabilities across the infrastructure.