Attack Surface: Malicious or Vulnerable Extensions (Flarum's Extension API)
- Description: Third-party extensions can introduce a wide range of vulnerabilities, from code execution to data breaches. While the vulnerability itself resides in the extension, Flarum's architecture is the enabler.
- How Flarum Contributes: Flarum's core design relies heavily on its extension API for functionality beyond the basic forum. This architectural dependency makes the extension ecosystem a central, and potentially vulnerable, part of any Flarum installation. Flarum's API provides the means for extensions to interact deeply with the core, increasing the potential impact of a compromised extension.
- Example: An extension designed to add custom profile fields contains a SQL injection vulnerability. An attacker exploits this to gain access to the entire database, including user data and potentially even server credentials (if stored insecurely).
- Impact: Complete system compromise, data theft, defacement, denial of service.
- Risk Severity: Critical
- Mitigation Strategies:
- Developers (Flarum Core): Continue to improve the security of the extension API. Consider implementing more granular permission controls for extensions. Provide clear security guidelines and best practices for extension developers. Explore sandboxing or isolation techniques for extensions.
- Developers (Extension): Conduct thorough code reviews. Follow secure coding practices. Use established libraries.
- Users: Only install extensions from trusted sources. Carefully review permissions. Keep extensions updated. Disable or remove unused extensions. Report suspected vulnerabilities. Use a staging environment.
Attack Surface: API Endpoint Vulnerabilities (Flarum's JSON:API)
- Description: Weaknesses in Flarum's core JSON:API endpoints, such as insufficient authentication, authorization, or input validation, can allow unauthorized access or manipulation of data.
- How Flarum Contributes: Flarum itself exposes a comprehensive JSON:API for interacting with the forum data. This API is a core component of Flarum and a primary target. The design and implementation of this API are entirely within Flarum's control.
- Example: An attacker discovers an API endpoint that allows creating new administrator accounts without proper authorization checks. They use this to gain full control of the forum.
- Impact: Data breaches, unauthorized data modification, denial of service, account takeover, complete forum compromise.
- Risk Severity: High
- Mitigation Strategies:
- Developers (Flarum Core): Rigorously review and test all API endpoints for authentication, authorization, and input validation vulnerabilities. Ensure that all endpoints enforce the principle of least privilege. Implement robust rate limiting to prevent abuse. Log all API requests and responses, paying particular attention to errors and unauthorized access attempts. Regularly conduct security audits of the API.
- Users: Keep Flarum updated. Monitor API logs (if accessible) for suspicious activity. Report any suspected API vulnerabilities to the Flarum team.
Attack Surface: Content Injection (Flarum's Core Rendering)
- Description: While Flarum uses a Markdown parser, vulnerabilities within Flarum's core handling of user-generated content (even after parsing) or in its interaction with the parser could lead to XSS or content spoofing. This is distinct from vulnerabilities within a third-party Markdown extension.
- How Flarum Contributes: Flarum's core code is responsible for taking the output of the Markdown parser (or any other content processing) and rendering it to the user. Any flaws in this core rendering process, or in the way Flarum handles user input before passing it to the parser, are Flarum's direct responsibility.
- Example: A bug in Flarum's core code allows an attacker to bypass the Markdown parser's sanitization by crafting a specially formatted post that exploits a flaw in how Flarum handles certain HTML entities after parsing.
- Impact: Cross-site scripting (XSS), content spoofing, defacement, session hijacking.
- Risk Severity: High
- Mitigation Strategies:
- Developers (Flarum Core): Ensure that all user-supplied content is properly sanitized and escaped at every stage of processing, including before and after parsing. Thoroughly test the interaction between Flarum's core rendering logic and the Markdown parser. Implement a robust Content Security Policy (CSP) to mitigate the impact of any XSS vulnerabilities that might slip through. Regularly review and update the Markdown parser and any related libraries.
- Users: Keep Flarum updated. Report any suspected content injection vulnerabilities to the Flarum team.
Attack Surface: Weak Authentication and Authorization (Flarum's Core Logic)
- Description: Flaws in Flarum's core authentication and authorization mechanisms (e.g., session management, password reset, permission checks) can lead to account compromise. This is distinct from vulnerabilities in authentication extensions.
- How Flarum Contributes: Flarum's core code handles user authentication, session management, and authorization checks. Any weaknesses in these core components are directly attributable to Flarum.
- Example: A flaw in Flarum's session management allows an attacker to hijack a user's session by predicting or stealing their session ID.
- Impact: Account takeover, data theft, unauthorized access to forum features.
- Risk Severity: High
- Mitigation Strategies:
- Developers (Flarum Core): Ensure Flarum's core authentication and authorization mechanisms adhere to industry best practices. Use secure, well-vetted libraries for cryptography and session management. Implement robust password reset procedures. Regularly review and test all authentication and authorization flows.
- Users: Keep Flarum updated. Use strong, unique passwords. Enable multi-factor authentication (MFA) if available (usually via an extension, but the underlying support must be present in Flarum's core).