CVE-2009-3593 in Freelancers
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Freelancers 1.0 allow remote attackers to inject arbitrary web script or HTML via the (1) id parameter to placebid.php and (2) jobid parameter to post_resume.php.
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Analysis
by VulDB Data Team • 05/21/2025
The vulnerability described in CVE-2009-3593 represents a critical cross-site scripting flaw affecting the Freelancers 1.0 web application, specifically targeting two distinct input parameters across different PHP scripts. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is one of the most prevalent and dangerous web application security flaws. The affected application processes user input without proper sanitization or output encoding, creating an environment where malicious actors can inject arbitrary web scripts or HTML content into the application's response. The vulnerability manifests in two separate attack vectors, demonstrating the application's widespread failure to validate and sanitize user-supplied data before incorporating it into dynamic web content.
The technical implementation of this vulnerability occurs through the improper handling of the id parameter in placebid.php and the jobid parameter in post_resume.php scripts. When these parameters are submitted to the respective PHP scripts without adequate input validation or sanitization, the application directly incorporates the user-supplied values into HTML output without proper encoding or escaping. This creates a condition where an attacker can craft malicious input containing script tags or other HTML elements that will be executed in the context of other users' browsers. The attack requires no authentication and can be executed remotely, making it particularly dangerous as it allows threat actors to compromise user sessions and potentially escalate their privileges within the application's ecosystem.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers to perform session hijacking, deface the application's content, redirect users to malicious sites, or steal sensitive information from authenticated users. The vulnerability affects the core functionality of the freelancers platform by compromising the integrity of user interactions and potentially exposing confidential information. According to ATT&CK framework, this vulnerability maps to T1531 - Account Access Token Manipulation, as successful exploitation could lead to unauthorized access to user accounts, and T1059 - Command and Scripting Interpreter, as attackers can execute malicious scripts within the browser context. The attack surface is particularly concerning given that these parameters are likely part of normal user workflows, making the exploitation more difficult to detect and prevent.
Mitigation strategies for this vulnerability must address the fundamental lack of input validation and output encoding in the affected application. The primary remediation involves implementing proper parameter validation and sanitization for all user-supplied inputs, particularly those used in dynamic content generation. The application should employ strict input validation that rejects or sanitizes any input containing potentially dangerous characters or script elements. Additionally, all output generated by the application must be properly encoded using appropriate context-specific encoding methods such as HTML entity encoding for HTML contexts, JavaScript encoding for script contexts, and URL encoding for URL contexts. Security headers such as Content Security Policy should be implemented to provide additional protection against XSS attacks, and the application should be regularly tested using automated scanning tools and manual penetration testing to identify similar vulnerabilities in other parts of the codebase. The remediation process should follow the OWASP Secure Coding practices and ensure that all user inputs are treated as untrusted data that requires proper validation and sanitization before processing or display.