CVE-2015-5356 in GetSimple
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in admin/filebrowser.php in GetSimple CMS before 3.3.6 allows remote attackers to inject arbitrary web script or HTML via the func parameter.
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Analysis
by VulDB Data Team • 05/22/2022
The CVE-2015-5356 vulnerability represents a critical cross-site scripting flaw discovered in GetSimple CMS versions prior to 3.3.6, specifically within the admin/filebrowser.php component. This vulnerability exposes the content management system to malicious injection attacks that can compromise user sessions and execute unauthorized code within the browser context of authenticated administrators. The flaw resides in the improper handling of the func parameter, which is processed without adequate input validation or output sanitization, creating a persistent vector for attacker exploitation.
The technical implementation of this vulnerability stems from the application's failure to properly sanitize user-supplied input passed through the func parameter in the filebrowser.php administrative interface. When an attacker crafts a malicious payload and submits it through this parameter, the system fails to validate or escape the input before processing it, allowing arbitrary HTML and JavaScript code to be executed within the browser of any user who accesses the affected page. This represents a classic case of improper input validation and output encoding, aligning with CWE-79 which catalogs improper neutralization of input during web page generation. The vulnerability specifically manifests as a reflected XSS attack since the malicious code is embedded in the URL and executed when the page is rendered.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the capability to escalate privileges and potentially gain full administrative control over affected GetSimple CMS installations. An attacker who successfully exploits this vulnerability can execute malicious scripts that may steal session cookies, redirect users to phishing sites, modify website content, or even establish persistent backdoors within the compromised system. The attack vector is particularly concerning because it targets the administrative interface, meaning that successful exploitation could result in complete system compromise. This vulnerability aligns with ATT&CK technique T1566 which describes social engineering attacks that can lead to privilege escalation through web application vulnerabilities.
The security implications of this flaw are particularly severe given that GetSimple CMS is widely used for small to medium-sized websites, making it a potentially attractive target for attackers seeking to compromise multiple sites simultaneously. The vulnerability's persistence across multiple versions indicates a fundamental flaw in the application's input handling mechanisms that required a dedicated patch release to address. Organizations utilizing GetSimple CMS prior to version 3.3.6 should immediately implement mitigations including patching to the latest version, implementing proper input validation measures, and conducting thorough security assessments of their web applications. Additionally, administrators should consider implementing web application firewalls and monitoring for suspicious parameter values that may indicate attempted exploitation of this vulnerability. The remediation process should also include comprehensive user education regarding the dangers of visiting untrusted links and the importance of maintaining current software versions to protect against known security flaws.