CVE-2005-2327 in e107
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in e107 0.617 and earlier allows remote attackers to inject arbitrary web script or HTML via nested [url] BBCode tags.
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Analysis
by VulDB Data Team • 06/16/2024
The vulnerability described in CVE-2005-2327 represents a critical cross-site scripting flaw affecting e107 version 0.617 and earlier installations. This vulnerability specifically targets the BBCode parsing functionality within the e107 content management system, creating a pathway for remote attackers to execute malicious scripts in the context of affected users' browsers. The flaw exploits the improper handling of nested [url] BBCode tags, which are commonly used for creating hyperlinks within the system's markup language. When users encounter maliciously crafted nested URL tags, the system fails to adequately sanitize the input, allowing attackers to inject arbitrary HTML and JavaScript code that executes in the victim's browser environment.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the e107 BBCode processor. The system processes nested [url] tags without sufficient sanitization of the contained attributes, particularly the href parameter that defines the target URL. Attackers can craft malicious BBCode sequences that include JavaScript event handlers or embedded script tags, which get executed when the parsed content is rendered in users' browsers. This represents a classic reflected XSS vulnerability where the malicious payload is injected through user-controllable input that gets immediately reflected back to the user without proper escaping or validation. The vulnerability falls under CWE-79, which specifically addresses Cross-Site Scripting flaws, and aligns with ATT&CK technique T1203, which covers Exploitation for Client Execution through web-based attacks.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, and redirection to malicious sites. An attacker could craft posts containing nested URL BBCode that, when viewed by other users, would steal their session cookies or redirect them to phishing sites. The vulnerability is particularly dangerous in community-driven platforms like e107 where users frequently post content and interact with others' contributions. The attack vector requires minimal privileges as it operates entirely through user-generated content, making it accessible to anyone with registration access to the platform. This creates a significant risk for website administrators who may not immediately notice malicious posts, especially if the system lacks proper content moderation or automated detection mechanisms.
Mitigation strategies for CVE-2005-2327 should focus on immediate patching of the e107 system to version 0.700 or later, which contains the necessary fixes for the BBCode parsing vulnerability. Organizations should implement comprehensive input validation and output encoding for all user-generated content, particularly within BBCode and HTML processing modules. The implementation of Content Security Policy headers can provide additional defense-in-depth against XSS attacks by restricting script execution within the browser context. Regular security audits and code reviews focusing on input sanitization routines are essential for identifying similar vulnerabilities in other components. The system should also enforce strict validation of URL parameters within BBCode tags, ensuring that any potentially malicious attributes are either stripped or properly encoded before rendering. Additionally, implementing automated monitoring for suspicious BBCode patterns and establishing proper user content moderation procedures can help detect and prevent exploitation attempts before they affect end users.