CVE-2006-0156 in Foxrum
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Foxrum 4.0.4f allows remote attackers to inject arbitrary Javascript via the javascript URI in bbcode url tags in (1) addpost1.php and (2) addtopic1.php.
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Analysis
by VulDB Data Team • 07/17/2018
The vulnerability described in CVE-2006-0156 represents a critical cross-site scripting flaw within the Foxrum 4.0.4f bulletin board system that exposes users to potential malicious code execution. This vulnerability specifically targets the bbcode url tag processing functionality, where the application fails to properly sanitize user input before rendering it in web pages. The flaw exists in two primary locations within the software's codebase namely addpost1.php and addtopic1.php which are responsible for handling new post and topic creation respectively. Attackers can exploit this weakness by crafting malicious bbcode url tags containing javascript URIs that bypass the application's input validation mechanisms.
The technical implementation of this vulnerability stems from insufficient sanitization of user-supplied data within the bbcode parsing engine. When users submit content containing bbcode url tags, the Foxrum application processes these tags without adequate validation of the URI schemes present in the href attributes. This oversight allows attackers to inject javascript code within the url parameter of bbcode tags, specifically targeting javascript URIs that execute arbitrary code when the malicious content is rendered in users' browsers. The vulnerability is particularly dangerous because it leverages the legitimate bbcode functionality to deliver malicious payloads, making detection more challenging for security systems that might not flag normal bbcode usage as suspicious.
The operational impact of this vulnerability extends beyond simple script injection to potentially compromise entire user sessions and enable sophisticated attack vectors. When a victim views a maliciously crafted post or topic containing the injected javascript code, the script executes within their browser context, potentially stealing session cookies, redirecting users to malicious sites, or performing actions on behalf of the user. This type of vulnerability can be exploited for account takeover, data exfiltration, and can serve as a launching point for more complex attacks within the compromised user environment. The vulnerability affects all users of the affected Foxrum version who view posts or topics containing the malicious content, creating a widespread potential impact across the entire forum community.
Organizations and system administrators should immediately implement multiple layers of defense to mitigate this vulnerability. The primary remediation involves updating to a patched version of Foxrum that properly sanitizes bbcode url tags and validates URI schemes before rendering user content. Additionally, implementing proper input validation and output encoding mechanisms can prevent similar issues in other applications. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications, and follows attack patterns documented in the ATT&CK framework under the T1203 technique for "Exploitation for Credential Access." Security measures should include regular vulnerability assessments, input validation testing, and monitoring for suspicious bbcode usage patterns that could indicate exploitation attempts. Organizations should also consider implementing web application firewalls and content security policies to provide additional protection against similar XSS vulnerabilities in their web applications.