CVE-2020-25730 in ZoneMinder
Summary
by MITRE • 04/04/2024
Cross Site Scripting (XSS) vulnerability in ZoneMinder before version 1.34.21, allows remote attackers execute arbitrary code, escalate privileges, and obtain sensitive information via PHP_SELF component in classic/views/download.php.
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Analysis
by VulDB Data Team • 08/30/2025
The vulnerability identified as CVE-2020-25730 represents a critical cross site scripting flaw in ZoneMinder versions prior to 1.34.21. This vulnerability specifically affects the classic/views/download.php component where the PHP_SELF variable is improperly handled, creating an exploitable entry point for malicious actors. The flaw resides in how the application processes and sanitizes user input within the download view functionality, allowing attackers to inject malicious scripts that execute in the context of other users' browsers.
This XSS vulnerability operates through the manipulation of the PHP_SELF server variable which contains the path of the current script. When ZoneMinder fails to properly sanitize this variable before rendering it in the web interface, attackers can craft malicious payloads that exploit the lack of input validation and output encoding. The vulnerability is particularly concerning because it enables attackers to execute arbitrary code within the victim's browser session, potentially leading to full compromise of the web application. The attack vector allows remote exploitation without requiring authentication, making it accessible to anyone who can interact with the ZoneMinder web interface.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to escalate privileges within the application context. An attacker could leverage this vulnerability to access sensitive information stored within the ZoneMinder system, including configuration details, user credentials, and surveillance data. The ability to execute code in the browser context also enables session hijacking attacks, where attackers can steal authentication tokens and impersonate legitimate users. This vulnerability directly maps to CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') and aligns with ATT&CK technique T1566.001 - Phishing: Spearphishing Attachment, as attackers could craft malicious download links to deliver payloads to unsuspecting users.
Organizations using ZoneMinder versions prior to 1.34.21 should immediately implement mitigations including input validation and output encoding for all user-supplied data, particularly in web interface components that handle file downloads. The most effective remediation involves upgrading to ZoneMinder version 1.34.21 or later, which includes proper sanitization of the PHP_SELF variable and enhanced input validation mechanisms. Additionally, implementing Content Security Policy headers can provide defense in depth against XSS attacks by restricting script execution within the application. Network segmentation and monitoring for suspicious download activities should also be implemented to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of proper input sanitization in web applications and highlights how seemingly innocuous server variables can become attack vectors when not properly handled.