CVE-2020-3953 in vRealize Log Insight
Summary
by MITRE
Cross Site Scripting (XSS) vulnerability exists in VMware vRealize Log Insight prior to 8.1.0 due to improper Input validation.
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Analysis
by VulDB Data Team • 05/07/2025
The vulnerability identified as CVE-2020-3953 represents a critical cross site scripting flaw in VMware vRealize Log Insight versions prior to 8.1.0, specifically classified under CWE-79 as improper neutralization of input during web output. This vulnerability arises from inadequate input validation mechanisms within the web application's processing pipeline, allowing malicious actors to inject arbitrary script code into the application's user interface. The affected system processes user-supplied data without sufficient sanitization or encoding, creating an exploitable condition that can be leveraged by attackers to execute malicious scripts within the context of a victim's browser session.
The technical implementation of this vulnerability occurs when the application fails to properly validate and sanitize user input before rendering it in web pages or log entries. Attackers can craft malicious payloads that, when processed by the vulnerable vRealize Log Insight instance, get executed in the browser of authenticated users who view the affected content. This typically involves injecting javascript code or other malicious scripts through form fields, log entries, or any user-controllable input parameters that are subsequently displayed without proper HTML encoding or output sanitization. The flaw exists at the application layer where input validation is insufficient to prevent the injection of script code that can be interpreted by web browsers.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, data exfiltration, and privilege escalation. An attacker who successfully exploits this vulnerability can potentially gain access to sensitive log data, manipulate system configurations, or even escalate privileges within the vRealize Log Insight environment. The vulnerability is particularly concerning in enterprise environments where vRealize Log Insight is used for security monitoring and log aggregation, as it can be leveraged to compromise the integrity of security operations and potentially provide attackers with access to critical system information.
Organizations should immediately implement mitigations including upgrading to VMware vRealize Log Insight version 8.1.0 or later, which contains the necessary patches to address the input validation deficiencies. Additional defensive measures include implementing proper input sanitization at all entry points, enabling content security policies, and conducting regular security assessments of the application's input handling mechanisms. The vulnerability aligns with ATT&CK technique T1059.007 for command and script injection, and represents a classic example of how inadequate input validation can lead to persistent security weaknesses in web applications. Security teams should also consider implementing web application firewalls and monitoring for suspicious input patterns that may indicate attempted exploitation of this and similar vulnerabilities.