CVE-2019-9508 in Avocent UMG-4000
Summary
by MITRE
The web interface of the Vertiv Avocent UMG-4000 version 4.2.1.19 is vulnerable to stored XSS. A remote attacker authenticated with an administrator account could store a maliciously named file within the web application that would execute each time a user browsed to the page.
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Analysis
by VulDB Data Team • 05/12/2024
The Vertiv Avocent UMG-4000 is a network management device used for remote monitoring and management of IT infrastructure equipment. This particular vulnerability affects version 4.2.1.19 of the web interface, which serves as the primary administrative access point for configuring and managing the device's operations. The device operates within critical infrastructure environments where unauthorized access could compromise entire network systems. The vulnerability exists within the file upload functionality of the web application, creating a persistent security weakness that allows attackers to execute malicious code against authenticated users.
The technical flaw stems from inadequate input validation and output encoding within the web application's file handling mechanisms. When administrators upload files through the web interface, the application fails to properly sanitize or validate the filenames and content, allowing malicious payloads to be stored within the system's file structure. This stored XSS vulnerability operates through a classic persistent attack vector where the malicious content is not reflected in the response but is instead stored on the server and executed when other users access the affected page. The vulnerability specifically targets the file naming functionality, enabling attackers to inject malicious JavaScript code into filenames that are then rendered in subsequent web page displays.
The operational impact of this vulnerability is severe as it provides attackers with a persistent foothold within the administrative interface. Once an attacker gains administrator credentials, they can upload malicious files that execute JavaScript code against any user who views the affected page. This creates a potential for privilege escalation attacks, session hijacking, and data exfiltration. The attack requires only administrative authentication, which may be obtained through credential compromise, weak password policies, or other authentication bypass techniques. The persistent nature of the vulnerability means that the malicious code continues to execute until manually removed from the system, providing attackers with long-term access to the device and potentially the broader network infrastructure.
Mitigation strategies should focus on implementing robust input validation and output encoding mechanisms throughout the web application. Organizations should immediately apply vendor patches if available and implement network segmentation to limit access to administrative interfaces. The principle of least privilege should be enforced by restricting administrative access to only necessary personnel and implementing strong authentication mechanisms including multi-factor authentication. Regular security assessments should include testing for stored XSS vulnerabilities in web applications, and input validation should be strengthened to prevent malicious payloads from being stored within the system. This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and represents a technique that could be categorized under ATT&CK tactic TA0001 (Initial Access) and technique T1190 (Exploit Public-Facing Application). Network monitoring should be enhanced to detect anomalous file upload activities and unusual administrative access patterns that may indicate exploitation attempts.