CVE-2018-10913 in glusterfs Server
Summary
by MITRE
An information disclosure vulnerability was discovered in glusterfs server. An attacker could issue a xattr request via glusterfs FUSE to determine the existence of any file.
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Analysis
by VulDB Data Team • 05/07/2023
The CVE-2018-10913 vulnerability represents a significant information disclosure flaw within the glusterfs distributed file system implementation. This vulnerability specifically affects the server component of glusterfs and manifests through improper handling of extended attributes requests. The flaw allows remote attackers to perform reconnaissance by issuing xattr requests through the glusterfs FUSE client interface, enabling them to determine whether specific files exist within the file system without requiring authentication or authorization. This type of vulnerability falls under the category of information disclosure as defined by CWE-200, where sensitive information about the system's file structure is exposed to unauthorized parties.
The technical implementation of this vulnerability stems from the glusterfs server's insufficient validation of extended attribute requests originating from FUSE clients. When a client issues an xattr request to check file attributes, the server responds differently based on whether the target file exists or not. This differential response behavior creates a side-channel attack vector where an attacker can enumerate files by observing the server's response patterns. The vulnerability specifically impacts the glusterfs server daemon which handles FUSE mount requests, making it exploitable in environments where glusterfs is deployed as a distributed storage solution. The flaw exists in the protocol handling layer where file existence checks are performed without proper access control enforcement.
The operational impact of CVE-2018-10913 extends beyond simple file enumeration as it provides attackers with valuable reconnaissance information that can be leveraged for subsequent attacks. An attacker who gains access to a glusterfs client can systematically determine the presence of sensitive files, directories, or data structures within the storage system. This reconnaissance capability aligns with ATT&CK technique T1083 (File and Directory Discovery) and can be used to map out the storage environment before attempting more sophisticated attacks such as privilege escalation or data exfiltration. The vulnerability particularly affects organizations using glusterfs for data storage in cloud environments, containerized applications, or distributed computing scenarios where file system metadata exposure could compromise overall security posture.
Mitigation strategies for this vulnerability require immediate patching of affected glusterfs server installations, as the flaw exists in the core protocol handling mechanisms. Organizations should implement network segmentation to limit access to glusterfs servers and restrict FUSE client connections to trusted networks. Additionally, monitoring and logging of xattr requests should be enabled to detect potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation and access control enforcement in distributed file systems, as outlined in CWE-284 for improper access control. Security teams should also consider implementing firewall rules that restrict FUSE protocol communication and regularly audit file system access patterns to identify unauthorized enumeration attempts. This vulnerability highlights the need for comprehensive security testing of distributed storage systems and proper adherence to security principles such as least privilege and defense in depth as recommended by industry security frameworks.