CVE-2017-11594 in Loomio
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Markdown parser in Loomio before 1.8.0 allows remote attackers to inject arbitrary web script or HTML via non-sanitized Markdown content in a new thread or a thread comment.
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Analysis
by VulDB Data Team • 12/13/2022
The CVE-2017-11594 vulnerability represents a critical cross-site scripting flaw within the Markdown parser implementation of the Loomio collaboration platform prior to version 1.8.0. This vulnerability resides in the sanitization process of user-generated content, specifically affecting how the system handles Markdown formatted text when creating new threads or adding comments to existing discussions. The flaw enables malicious actors to inject arbitrary web scripts or HTML code directly into the platform's content rendering pipeline, potentially compromising the security of all users interacting with the affected system.
The technical nature of this vulnerability stems from insufficient input validation and sanitization within the Markdown parsing component of Loomio's backend processing system. When users submit content containing Markdown formatting, the parser fails to properly sanitize potentially malicious payloads that could contain script tags, event handlers, or other XSS vectors. This weakness allows attackers to craft specially formatted Markdown content that, when rendered by the application, executes arbitrary JavaScript code within the context of other users' browsers. The vulnerability specifically affects the thread creation and comment posting functionalities, making it particularly dangerous in collaborative environments where multiple users interact with shared content.
The operational impact of CVE-2017-11594 extends beyond simple data theft or defacement, as it can enable sophisticated attack chains including session hijacking, credential theft, and privilege escalation within the application. Attackers can leverage this vulnerability to execute malicious code in the context of authenticated users, potentially gaining access to sensitive discussions, personal information, or administrative controls. The vulnerability affects all users of Loomio versions prior to 1.8.0, making it particularly dangerous in environments where multiple stakeholders collaborate on sensitive projects or discussions. The attack vector requires minimal technical expertise, as the vulnerability can be exploited through standard web interface interactions without requiring specialized tools or deep knowledge of the underlying system architecture.
This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications, and maps to ATT&CK technique T1059.007 for script injection. Organizations should implement immediate mitigations including updating to Loomio version 1.8.0 or later, implementing comprehensive input sanitization for all user-generated content, and deploying content security policies to prevent unauthorized script execution. Additional defensive measures include regular security audits of third-party components, implementing proper output encoding for all rendered content, and establishing robust monitoring for suspicious content patterns. The vulnerability demonstrates the critical importance of proper input validation in web applications and highlights the need for comprehensive security testing of all user-facing interfaces to prevent similar issues in collaborative software platforms.