CVE-2005-0857 in CoolForum
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in avatar.php for CoolForum 0.8 and earlier allows remote attackers to inject arbitrary web script or HTML via the img parameter.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 06/01/2025
The vulnerability identified as CVE-2005-0857 represents a classic cross-site scripting flaw in the CoolForum 0.8 software suite, specifically within the avatar.php component. This issue arises from inadequate input validation and output sanitization mechanisms that fail to properly handle user-supplied data. The vulnerability is particularly concerning as it affects the avatar functionality, which is a common feature in web forums where users can upload or specify images to represent themselves. The img parameter serves as the primary attack vector, allowing malicious actors to inject arbitrary web scripts or HTML code that gets executed in the context of other users' browsers when they view the affected forum page.
The technical implementation of this vulnerability stems from the software's failure to sanitize user input before incorporating it into dynamic web content. When a user specifies an avatar image through the img parameter, the application directly incorporates this input into the HTML output without proper validation or encoding. This creates an environment where an attacker can craft malicious input containing script tags or other HTML elements that execute in the browser context of legitimate users. The vulnerability is classified as a reflected XSS attack since the malicious payload is embedded in the URL or form data and reflected back to the user's browser. This flaw aligns with CWE-79 which specifically addresses Cross-Site Scripting vulnerabilities in web applications.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable sophisticated attacks such as session hijacking, credential theft, or redirection to malicious websites. An attacker could craft a payload that steals session cookies from authenticated users, effectively allowing them to impersonate legitimate forum members. The attack requires minimal technical expertise and can be executed through simple URL manipulation, making it particularly dangerous for widespread exploitation. Given that CoolForum was a web-based application, the vulnerability affects users across different browsers and platforms, as the XSS flaw operates at the application layer rather than being dependent on specific browser vulnerabilities. This makes the impact more pervasive and difficult to contain within a single user base or environment.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and output encoding mechanisms. The most effective approach involves sanitizing all user input through strict validation that rejects or encodes potentially dangerous characters and patterns. Implementing Content Security Policy headers can provide an additional layer of protection by restricting the sources from which scripts can be loaded. The application should also employ proper HTML encoding when displaying user-supplied content, ensuring that special characters are converted to their safe HTML entities. For the specific case of avatar.php, the software should validate that the img parameter contains only legitimate image URLs or file paths, rejecting any input that appears to contain executable code. Organizations should also consider implementing web application firewalls that can detect and block suspicious input patterns. This vulnerability demonstrates the critical importance of input validation and output encoding in preventing XSS attacks, aligning with ATT&CK technique T1203 which covers credential access through web application vulnerabilities. The remediation process should include comprehensive code review to identify similar patterns throughout the application and ensure that all user-supplied data is properly handled before being incorporated into dynamic web content.