CVE-2005-0477 in IP.Board
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the SML code for Invision Power Board 1.3.1 FINAL allows remote attackers to inject arbitrary web script via (1) a signature file or (2) a message post containing an IMG tag within a COLOR tag whose style is set to background:url.
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Analysis
by VulDB Data Team • 07/28/2025
The CVE-2005-0477 vulnerability represents a critical cross-site scripting flaw discovered in Invision Power Board version 1.3.1 FINAL, specifically within its SML (Simple Markup Language) code processing functionality. This vulnerability exists in the forum software's handling of user-generated content, particularly when processing signature files and message posts that contain specially crafted HTML markup. The flaw demonstrates a classic XSS vulnerability pattern where user input is not properly sanitized or validated before being rendered back to other users, creating an avenue for malicious actors to execute arbitrary web scripts in the context of victim browsers.
The technical exploitation of this vulnerability occurs through two distinct vectors that leverage the forum software's permissive HTML parsing behavior. The first attack vector involves injecting malicious code into signature files, which are typically displayed alongside user posts and are processed through the SML parser. The second vector targets message posts containing an IMG tag nested within a COLOR tag where the style attribute is manipulated to include background:url functionality. This specific combination exploits the software's inadequate input filtering mechanisms, particularly its failure to properly sanitize nested HTML tags and CSS style attributes that could be used to load external resources or execute JavaScript code.
From an operational perspective, this vulnerability presents significant risks to forum administrators and users alike, as it allows remote attackers to execute persistent XSS attacks that can compromise user sessions, steal cookies, redirect users to malicious sites, or deface the forum interface. The impact extends beyond simple data theft, as attackers can leverage the vulnerability to establish persistent backdoors through the forum's user interface, potentially using the platform as a staging area for more sophisticated attacks. The vulnerability's exploitation requires minimal technical skill and can be automated, making it particularly dangerous in public forums where users may not be security-aware.
Security professionals should note that this vulnerability aligns with CWE-79, which specifically addresses Cross-Site Scripting flaws in software applications. The attack pattern also corresponds to techniques documented in the MITRE ATT&CK framework under T1059.007 for Command and Scripting Interpreter: JavaScript, and T1566 for Phishing with Social Engineering. The vulnerability's persistence through signature files and message posts creates a particularly challenging remediation scenario, as administrators must not only patch the software but also audit existing content for malicious payloads that may have already been injected. The recommended mitigation strategy involves implementing comprehensive input validation and output encoding, upgrading to patched versions of Invision Power Board, and establishing strict content filtering policies that prevent the execution of embedded scripts within user-generated content.
The broader implications of CVE-2005-0477 highlight the critical importance of proper HTML sanitization in web applications, particularly those that allow user-generated content. This vulnerability serves as a prime example of how seemingly benign features like colored text and image embedding can become attack vectors when proper security controls are not implemented. Organizations running legacy forum software should prioritize immediate patching and consider implementing web application firewalls to detect and block similar attacks targeting other vulnerable applications within their infrastructure. The vulnerability also underscores the necessity of regular security assessments and the importance of maintaining up-to-date software versions to protect against known exploits that have been documented in security databases for years.