CVE-2012-3832 in decoda
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in decoda/Decoda.php in Decoda before 3.2 allows remote attackers to inject arbitrary web script or HTML via vectors related to (1) b or (2) div tags.
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Analysis
by VulDB Data Team • 12/05/2021
The CVE-2012-3832 vulnerability represents a critical cross-site scripting flaw within the Decoda library version 3.1 and earlier, which is a PHP-based text parser and formatter commonly used in web applications for processing user-generated content. This vulnerability specifically affects the decoda/Decoda.php file where the library fails to properly sanitize user input when processing bbcode-style tags, creating an avenue for malicious actors to execute arbitrary web scripts or HTML code within the context of affected applications. The vulnerability manifests through two primary attack vectors involving the b and div tag processing mechanisms, which are fundamental components of the library's markup handling system.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the Decoda library's parsing routines. When the library processes user-supplied content containing bbcode tags such as [b] or [div], it fails to adequately sanitize the attributes and content associated with these tags before rendering them in the final HTML output. This improper sanitization allows attackers to inject malicious payloads that can execute within the browser context of other users who view the affected content. The vulnerability is classified as a classic reflected XSS issue where the malicious script is executed when the parsed content is displayed to end users, making it particularly dangerous in web applications where user-generated content is prevalent.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, defacement of web applications, and redirection to malicious sites. In a typical attack scenario, an attacker would submit specially crafted content containing malicious scripts within the b or div tags, which would then be processed by the vulnerable Decoda library and executed when other users view the content. This vulnerability is particularly concerning because it affects the underlying parsing library rather than individual applications, meaning that any application using Decoda versions prior to 3.2 could be compromised, creating a widespread potential attack surface across numerous web platforms and services.
Mitigation strategies for this vulnerability center around immediate version upgrades to Decoda 3.2 or later, which contain the necessary patches to address the input sanitization issues. Security teams should also implement additional defensive measures including comprehensive input validation, output encoding, and content security policies to reduce the potential impact of similar vulnerabilities. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in software applications, and represents a common weakness in web application security frameworks. From an ATT&CK perspective, this vulnerability maps to T1059.007 for script injection techniques and T1566 for social engineering through malicious content delivery, highlighting the multi-faceted nature of the threat. Organizations should conduct thorough vulnerability assessments to identify all instances where Decoda is utilized and ensure proper patch management procedures are in place to prevent exploitation of this and similar vulnerabilities in their web applications.