CVE-2009-2785 in PHP Open Classifieds Script
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in PHP Open Classifieds Script allow remote attackers to inject arbitrary web script or HTML via the (1) page parameter to buy.php and the id parameter to (2) contact.php and (3) tellafriend.php.
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Analysis
by VulDB Data Team • 12/23/2017
The CVE-2009-2785 vulnerability represents a critical cross-site scripting flaw in the PHP Open Classifieds Script platform that exposes multiple entry points for remote attackers to execute malicious code within victim browsers. This vulnerability specifically targets three distinct files within the application framework where user input is improperly sanitized, creating persistent security gaps that can be exploited by threat actors to compromise user sessions and execute unauthorized actions. The affected parameters include the page parameter in buy.php and the id parameter in both contact.php and tellafriend.php, demonstrating the widespread nature of the input validation failure across the application's core functionality.
The technical implementation of this vulnerability stems from inadequate input sanitization mechanisms within the PHP Open Classifieds Script codebase. When users submit data through the identified parameters, the application fails to properly validate or escape the input before processing or displaying it back to users. This creates a classic XSS attack vector where malicious scripts can be injected and subsequently executed in the context of other users' browsers. The vulnerability manifests as reflected XSS since the malicious content is immediately reflected back to users without proper encoding or filtering of special characters that could be interpreted as HTML or JavaScript commands.
From an operational impact perspective, this vulnerability poses significant risks to both end users and system administrators. Attackers can leverage these XSS flaws to steal session cookies, redirect users to malicious websites, deface the classifieds platform, or execute arbitrary commands on behalf of authenticated users. The attack surface is particularly concerning given that the vulnerable parameters are commonly used in the application's core functionality, meaning legitimate users frequently interact with these endpoints during normal browsing activities. This increases the likelihood of successful exploitation and makes the vulnerability particularly dangerous for platforms handling sensitive user data and transactions.
The vulnerability aligns with CWE-79, which specifically addresses Cross-Site Scripting flaws in software applications, and demonstrates how improper input handling can create persistent security weaknesses that affect multiple application modules. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 (Phishing via Social Media) and T1059.007 (Command and Scripting Interpreter: JavaScript) as attackers can leverage these flaws to execute malicious JavaScript code and potentially establish persistent access to user sessions. The attack chain typically involves crafting malicious payloads that exploit the vulnerable parameters and then delivering these payloads through social engineering tactics or by embedding them in legitimate-looking classified listings.
Effective mitigation strategies for this vulnerability require immediate implementation of proper input validation and output encoding mechanisms throughout the PHP Open Classifieds Script platform. System administrators should implement comprehensive parameter sanitization routines that escape special characters and validate input against expected data types before processing. The solution should include the implementation of Content Security Policy headers to prevent unauthorized script execution, regular security audits of input handling mechanisms, and application-level filtering that prevents the execution of potentially dangerous JavaScript code. Additionally, upgrading to patched versions of the PHP Open Classifieds Script or implementing web application firewalls that can detect and block malicious input patterns would provide layered defense against exploitation attempts.