CVE-2021-20701 in Disk Agent CLUSTERPRO X
Summary
by MITRE • 11/03/2021
Buffer overflow vulnerability in the Disk Agent CLUSTERPRO X 1.0 for Windows and later, EXPRESSCLUSTER X 1.0 for Windows and later allows attacker to remote code execution via a network.
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Analysis
by VulDB Data Team • 11/06/2021
The buffer overflow vulnerability identified as CVE-2021-20701 affects the Disk Agent component of Fujitsu's ClusterPRO X and EXPRESSCLUSTER X software versions for Windows. This vulnerability exists within the network communication handling mechanisms of the Disk Agent service, which is responsible for managing disk-related operations in clustered environments. The flaw represents a critical security weakness that can be exploited remotely, potentially allowing attackers to execute arbitrary code on affected systems.
The technical implementation of this vulnerability stems from inadequate input validation within the network protocol handling code of the Disk Agent service. When processing network requests containing specially crafted data, the service fails to properly bounds-check buffer allocations, leading to memory corruption that can be leveraged for code execution. This type of vulnerability maps directly to CWE-121, which describes heap-based buffer overflow conditions, and CWE-787, which addresses out-of-bounds write vulnerabilities. The vulnerability occurs during the processing of network packets that are sent to the Disk Agent service, making it particularly dangerous as it can be exploited without requiring local system access.
The operational impact of this vulnerability extends beyond simple remote code execution, as it fundamentally compromises the integrity and availability of clustered systems. Attackers who successfully exploit this vulnerability can gain full control over affected systems, potentially leading to data theft, system compromise, and disruption of business continuity operations. In clustered environments where EXPRESSCLUSTER X and ClusterPRO X are deployed, this vulnerability could enable attackers to escalate privileges and move laterally within the network infrastructure. The attack surface is particularly concerning given that the vulnerability is accessible over the network, meaning that attackers do not need physical access or prior authentication to exploit the flaw.
Mitigation strategies for CVE-2021-20701 should prioritize immediate patch deployment from Fujitsu, as this represents the most effective defense against exploitation. Organizations should also implement network segmentation and firewall rules to restrict access to the affected Disk Agent service ports, limiting the attack surface. According to ATT&CK framework, this vulnerability would be categorized under T1203, which covers exploitation for privilege escalation, and T1071.004, which covers application layer protocol usage for command and control. Network monitoring should be enhanced to detect anomalous traffic patterns that might indicate exploitation attempts, while system administrators should implement strict access controls and regularly audit network communications to identify potential malicious activity.
The broader implications of this vulnerability highlight the critical importance of secure coding practices in enterprise software, particularly in systems that manage critical infrastructure components. This flaw demonstrates how seemingly minor input validation issues can result in severe security consequences, emphasizing the need for comprehensive security testing and vulnerability assessments throughout the software development lifecycle. Organizations should also consider implementing intrusion detection systems and regular security assessments to identify similar vulnerabilities in their infrastructure components and prevent exploitation attempts that could lead to catastrophic system compromise and data breaches.