CVE-2009-4937 in Small Pirate
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Small Pirate (SPirate) 2.1 allows remote attackers to inject arbitrary web script or HTML via an onmouseover action in an img BBCode tag within a url BBCode tag.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/05/2018
The CVE-2009-4937 vulnerability represents a critical cross-site scripting flaw discovered in Small Pirate (SPirate) version 2.1, a web application framework that was widely used for creating bulletin board systems and content management platforms. This vulnerability specifically targets the application's handling of BBCode input processing, which is a simplified markup language commonly used in forums and discussion platforms to format text and embed media elements. The flaw occurs when the application fails to properly sanitize user input containing BBCode tags, particularly when processing nested BBCode structures that combine url and img tags with event handlers.
The technical exploitation of this vulnerability hinges on the improper sanitization of BBCode elements within the application's rendering engine. Attackers can craft malicious input by embedding an img BBCode tag that contains an onmouseover JavaScript event handler, which is then nested within a url BBCode tag. When the vulnerable application processes this malformed input, it fails to adequately filter or escape the embedded JavaScript code, allowing the malicious script to execute within the context of other users' browsers. This represents a classic reflected XSS vulnerability where the malicious payload is delivered through user-generated content and executed when other users view the affected content.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers to perform a wide range of malicious activities including session hijacking, credential theft, and data exfiltration. The vulnerability's exploitation does not require authentication, making it particularly dangerous as any user with access to the forum or content management system could potentially inject malicious code. This flaw directly violates security principles outlined in the OWASP Top Ten, specifically addressing the prevention of cross-site scripting vulnerabilities and the importance of input validation and output encoding. The vulnerability also aligns with CWE-79, which describes cross-site scripting flaws in web applications, and demonstrates the critical need for proper HTML and JavaScript sanitization in web applications.
Mitigation strategies for this vulnerability should encompass multiple layers of defense including immediate patching of the vulnerable SPirate version to address the BBCode parsing flaw, implementation of comprehensive input validation and sanitization routines, and deployment of web application firewalls to detect and block malicious payloads. Organizations should also implement proper output encoding for all user-generated content, particularly when rendering BBCode elements that may contain embedded HTML or JavaScript. The vulnerability's characteristics make it particularly susceptible to automated exploitation, therefore security teams should monitor for suspicious content and implement content security policies to prevent execution of unauthorized scripts. Additionally, regular security assessments and code reviews should be conducted to identify similar input validation flaws in other parts of the application stack, as this vulnerability demonstrates how improper handling of user input can create persistent security risks in web applications.
This vulnerability exemplifies the broader challenges faced by web application developers in properly handling user input across multiple markup languages and formats, and highlights the importance of adhering to established security frameworks and standards. The attack vector demonstrates how seemingly benign functionality like BBCode support can become a security liability when proper input validation is not implemented, underscoring the principle that all user-provided data should be treated as potentially malicious and thoroughly sanitized before processing or display.