CVE-2020-5319 in EMC Unity
Summary
by MITRE
Dell EMC Unity, Dell EMC Unity XT, and Dell EMC UnityVSA versions prior to 5.0.2.0.5.009 contain a Denial of Service vulnerability on NAS Server SSH implementation that is used to provide SFTP service on a NAS server. A remote unauthenticated attacker may potentially exploit this vulnerability and cause a Denial of Service (Storage Processor Panic) by sending an out of order SSH protocol sequence.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 03/28/2024
The vulnerability identified as CVE-2020-5319 affects Dell EMC Unity family storage systems including Unity, Unity XT, and UnityVSA appliances running firmware versions prior to 5.0.2.0.5.009. This security flaw resides within the Network Attached Storage (NAS) Server SSH implementation that provides Secure File Transfer Protocol (SFTP) services to remote clients. The issue represents a significant concern for enterprise storage environments where uninterrupted access to critical data services is paramount for business operations. The vulnerability specifically targets the SSH protocol handling within the storage system's NAS server component, creating a potential pathway for malicious actors to disrupt essential storage services.
The technical flaw manifests through improper handling of SSH protocol sequences within the storage system's NAS server implementation. An attacker can exploit this weakness by sending out-of-order SSH protocol sequences to the affected storage appliances without requiring authentication credentials. This particular vulnerability is classified as a Denial of Service condition that can trigger what is known as a "Storage Processor Panic" - a critical system failure state that results in complete service disruption. The vulnerability operates at the protocol level within the SSH implementation, making it particularly dangerous as it can be exploited remotely without the need for valid credentials or prior access to the system. The flaw essentially allows an unauthenticated attacker to cause the storage processor to crash or become unresponsive, effectively rendering the SFTP service unavailable to legitimate users.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise business continuity and data availability. Organizations relying on Dell EMC Unity storage systems for their critical data operations face significant risk when operating vulnerable firmware versions, as a successful exploitation could result in extended downtime for storage services. The SFTP service disruption affects file transfer operations, backup processes, and any other applications dependent on secure file transfer capabilities within the storage environment. This vulnerability particularly affects enterprises with distributed storage infrastructures where remote access to storage services is common, as the attack vector requires no authentication and can be executed from any network location. The potential for cascading effects exists if the storage system serves as a critical component in larger data processing workflows or backup operations.
Mitigation strategies for CVE-2020-5319 primarily focus on firmware updates to the affected Dell EMC Unity appliances. Organizations should immediately upgrade their storage systems to firmware version 5.0.2.0.5.009 or later, which contains the necessary patches to address the SSH protocol handling vulnerability. Network segmentation and access controls should be implemented to limit exposure of the affected storage appliances to untrusted networks, while monitoring systems should be configured to detect anomalous SSH traffic patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-200, which covers "Information Exposure," as it allows unauthorized access to system resources through protocol manipulation, and relates to ATT&CK technique T1499.001 for "Network Denial of Service" which encompasses methods to disrupt network services through protocol-level attacks. Additionally, this vulnerability demonstrates characteristics of a privilege escalation vector through service disruption, potentially impacting availability and integrity of critical storage services within enterprise environments.