CVE-2018-14659 in GlusterFS
Summary
by MITRE
The Gluster file system through versions 4.1.4 and 3.1.2 is vulnerable to a denial of service attack via use of the 'GF_XATTR_IOSTATS_DUMP_KEY' xattr. A remote, authenticated attacker could exploit this by mounting a Gluster volume and repeatedly calling 'setxattr(2)' to trigger a state dump and create an arbitrary number of files in the server's runtime directory.
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability identified as CVE-2018-14659 affects the Gluster file system across versions 3.1.2 through 4.1.4, representing a significant denial of service weakness that can be exploited by remote authenticated attackers. This flaw specifically targets the file system's handling of extended attributes, particularly the 'GF_XATTR_IOSTATS_DUMP_KEY' xattr which serves as an entry point for malicious activity. The vulnerability operates through a carefully crafted sequence of system calls that can be executed against mounted Gluster volumes, making it particularly dangerous in networked environments where multiple users may have access to file system resources.
The technical mechanism behind this vulnerability involves the exploitation of the setxattr system call functionality within the Gluster file system implementation. When an authenticated attacker mounts a Gluster volume and repeatedly invokes setxattr with the specific 'GF_XATTR_IOSTATS_DUMP_KEY' extended attribute, the system triggers an internal state dump mechanism. This mechanism is designed for diagnostic purposes but becomes exploitable when abused through repeated invocation. The flaw stems from inadequate input validation and resource management within the extended attribute handling code, specifically in how the system processes and responds to repeated state dump requests.
The operational impact of this vulnerability extends beyond simple service disruption, creating a persistent resource exhaustion condition that can severely degrade system performance or completely halt file system operations. Each invocation of the vulnerable extended attribute triggers the creation of new files within the server's runtime directory structure, potentially leading to disk space exhaustion and cascading failures throughout the storage infrastructure. The attacker can maintain this denial of service condition indefinitely by continuously submitting the malicious extended attribute requests, making it particularly challenging to detect and mitigate without proper monitoring and access controls. This vulnerability directly maps to CWE-400, which addresses "Uncontrolled Resource Consumption" in software systems, and aligns with ATT&CK technique T1499.004 for "File System Wipe" and T1565.001 for "Data Manipulation" through resource exhaustion attacks.
Mitigation strategies for CVE-2018-14659 require immediate implementation of access controls and monitoring mechanisms to prevent unauthorized extended attribute manipulation. System administrators should implement strict access controls on Gluster volumes, limiting the ability of authenticated users to manipulate extended attributes, particularly those related to system diagnostics. The most effective immediate solution involves patching affected Gluster versions to 4.1.5 or later, which includes fixes for the extended attribute handling logic. Additionally, implementing monitoring for excessive setxattr operations and establishing automated alerts for unusual file creation patterns in runtime directories can help detect exploitation attempts. Network segmentation and privilege separation should be enforced to limit the scope of potential attacks, while regular security audits of extended attribute usage patterns can help identify anomalous behavior that might indicate exploitation attempts. The vulnerability also underscores the importance of input validation and resource management practices, particularly in systems that expose diagnostic interfaces through extended attribute mechanisms, aligning with security best practices outlined in NIST SP 800-125 and ISO/IEC 27001 standards for secure system design and implementation.