CVE-2016-4897 in Usermin
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in (1) filter/save_forward.cgi, (2) filter/save.cgi, (3) /man/search.cgi in Usermin before 1.690.
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Analysis
by VulDB Data Team • 08/29/2020
The vulnerability identified as CVE-2016-4897 represents a critical security flaw affecting Usermin versions prior to 1.690, specifically targeting three distinct CGI scripts that handle user input processing. These scripts including filter/save_forward.cgi, filter/save.cgi, and man/search.cgi all exhibit cross-site scripting vulnerabilities that allow malicious actors to inject arbitrary JavaScript code into the application's response. The flaw stems from insufficient input validation and output encoding mechanisms within these components, creating persistent opportunities for attackers to exploit the system through web-based malicious payloads.
This vulnerability operates under the Common Weakness Enumeration framework as CWE-79, which categorizes cross-site scripting flaws as weaknesses in web applications that enable attackers to inject client-side scripts into web pages viewed by other users. The affected Usermin components process user-supplied data without proper sanitization, allowing attackers to craft malicious input that gets executed in the context of other users' browsers when they access the vulnerable pages. The exploitation occurs through the manipulation of parameters passed to these CGI scripts, where the application fails to properly encode or validate user input before rendering it in web responses.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the capability to perform session hijacking, deface web interfaces, steal user credentials, and potentially escalate privileges within the Usermin environment. When users browse to pages containing malicious scripts, the injected code executes in their browser context, potentially allowing attackers to access sensitive information, modify user settings, or redirect users to malicious websites. The persistent nature of these XSS flaws means that once exploited, the malicious code can affect multiple users who access the vulnerable application, making the impact particularly severe in multi-user environments.
Mitigation strategies for CVE-2016-4897 require immediate patching of Usermin to version 1.690 or later, which includes proper input validation and output encoding fixes for the affected scripts. Organizations should implement comprehensive web application firewall rules to detect and block suspicious input patterns targeting these specific CGI endpoints, while also conducting thorough security assessments of all web-based applications to identify similar vulnerabilities. The remediation process should include validating that all user input is properly escaped before being rendered in web responses, implementing Content Security Policy headers to limit script execution, and conducting regular security testing to ensure that similar vulnerabilities do not exist in other application components. Additionally, security teams should monitor for exploitation attempts through network traffic analysis and implement proper logging to track access to vulnerable endpoints, aligning with the attack techniques documented in the MITRE ATT&CK framework under the web application exploitation category.