CVE-2014-3876 in fex
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Frams Fast File EXchange (F*EX, aka fex) before fex-20140530 allow remote attackers to inject arbitrary web script or HTML via the (1) akey parameter to rup or (2) disclaimer or (3) gm parameter to fuc.
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Analysis
by VulDB Data Team • 03/22/2022
The vulnerability identified as CVE-2014-3876 represents a critical cross-site scripting flaw in Frams Fast File EXchange (F*EX) software, specifically affecting versions prior to fex-20140530. This web-based application facilitates file sharing and management operations, making it a potential target for malicious actors seeking to exploit client-side vulnerabilities. The flaw manifests in three distinct parameter injection points that collectively undermine the application's security posture and user protection mechanisms.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the F*EX application's request handling processes. Attackers can exploit the vulnerability by manipulating three specific parameters: akey parameter in the rup endpoint, disclaimer parameter, and gm parameter in the fuc endpoint. These parameters fail to properly sanitize user-supplied input before incorporating it into dynamic web responses, creating opportunities for malicious script injection. The vulnerability directly maps to CWE-79, which defines Cross-Site Scripting as a weakness where untrusted data is incorporated into web page content without proper validation or encoding, allowing attackers to execute arbitrary scripts in the victim's browser context.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers to perform various malicious activities including session hijacking, credential theft, and data exfiltration. When victims interact with compromised web pages, the injected scripts can access sensitive session cookies, potentially allowing unauthorized access to user accounts and file repositories. The vulnerability affects the application's core functionality by compromising the integrity of user interactions and potentially enabling privilege escalation attacks. Organizations utilizing F*EX for file sharing operations face significant risk exposure, particularly in environments where users may encounter maliciously crafted links or files.
The exploitation of CVE-2014-3876 aligns with ATT&CK technique T1059.007, which describes the use of scripting languages for execution within web applications. Attackers can leverage this vulnerability to establish persistent access through malicious JavaScript payloads that maintain session state across multiple requests. The attack surface is particularly concerning given F*EX's intended use in file sharing environments where users frequently interact with external content and links. Security professionals should consider this vulnerability in relation to broader web application security frameworks and ensure comprehensive testing of input validation mechanisms across all application endpoints.
Mitigation strategies for this vulnerability require immediate implementation of proper input sanitization and output encoding mechanisms throughout the affected application components. Organizations should deploy web application firewalls with XSS detection capabilities and implement Content Security Policy headers to limit script execution. The most effective remediation involves upgrading to F*EX version fex-20140530 or later, which contains the necessary patches to address the input validation gaps. Regular security assessments and code reviews should be implemented to identify similar vulnerabilities in other application components, with particular attention to parameter handling in dynamic web applications. Additionally, user education regarding suspicious links and file downloads remains crucial for reducing the attack surface and preventing successful exploitation attempts.