sec-design-deep-analysis.md

Deep Security Analysis of reveal.js Application

1. Objective, Scope, and Methodology

Objective:

This deep security analysis aims to thoroughly evaluate the security posture of reveal.js, a popular open-source HTML presentation framework. The objective is to identify potential security vulnerabilities and risks associated with its architecture, components, and deployment, and to provide actionable, reveal.js-specific mitigation strategies. The analysis will focus on understanding the security implications for users creating and viewing presentations built with reveal.js, ensuring the framework can be used securely for various presentation needs.

Scope:

This analysis encompasses the following aspects of reveal.js, as outlined in the provided Security Design Review:

• reveal.js Library: Security of the core JavaScript, CSS, and HTML framework, including its dependencies and plugin ecosystem.
• Presentation Content: Security considerations related to user-created presentation files (HTML, CSS, JavaScript, media) and the potential for introducing vulnerabilities through custom content.
• Deployment Environments: Security implications of different deployment options, specifically focusing on static hosting on web servers and CDNs.
• Build Process: Security of the development and build pipeline, including dependency management and artifact creation.
• User Interaction: Security considerations related to users viewing and interacting with reveal.js presentations in web browsers.
• Security Controls: Evaluation of existing, accepted, and recommended security controls as defined in the Security Design Review.

The analysis will specifically focus on client-side security vulnerabilities inherent in web applications and the unique aspects of a presentation framework like reveal.js. It will not delve into general web server or network security beyond their direct relevance to reveal.js deployments.

Methodology:

This deep analysis will employ the following methodology:

1. Architecture and Data Flow Inference: Based on the provided C4 diagrams (Context, Container, Deployment, Build) and the Security Design Review documentation, we will infer the architecture, key components, and data flow of reveal.js. This will involve understanding how users interact with presentations, how the library is loaded and executed, and how presentation content is processed.
2. Component-Specific Security Implication Analysis: Each key component identified in the C4 diagrams and the Security Design Review will be analyzed for potential security vulnerabilities. This will involve considering common web application security risks such as Cross-Site Scripting (XSS), dependency vulnerabilities, Content Security Policy (CSP) bypasses, and Subresource Integrity (SRI) issues, tailored to the context of reveal.js.
3. Threat Modeling: We will implicitly perform threat modeling by considering the business risks and security posture outlined in the Security Design Review. We will identify potential threats that could exploit vulnerabilities in reveal.js or its deployment, focusing on the impact on business priorities and sensitive data (presentation content).
4. Mitigation Strategy Development: For each identified security implication and potential threat, we will develop specific, actionable, and tailored mitigation strategies. These strategies will be directly applicable to reveal.js and its usage, drawing from the recommended security controls in the Security Design Review and industry best practices for web application security.
5. Actionable Recommendations: The analysis will culminate in a set of actionable recommendations for the reveal.js development team and users, focusing on enhancing the security of the framework and its deployments. These recommendations will be practical, prioritized, and directly address the identified security concerns.

2. Security Implications of Key Components

Based on the C4 diagrams and Security Design Review, we can break down the security implications of key components as follows:

A. Presentation Viewers (Users & Web Browser)

• Component: Users viewing presentations through Web Browsers.
• Data Flow: Users' browsers request presentation files (HTML, CSS, JS, media) from the Web Server/CDN. The browser then executes reveal.js library and renders the presentation content.
• Security Implications:
  • Client-Side Execution Risks: The browser environment is inherently trusted for executing JavaScript. If the presentation content or reveal.js library is compromised (e.g., via XSS or dependency vulnerability), malicious JavaScript could be executed within the user's browser. This could lead to:
    • Data theft: Access to browser cookies, local storage, or session data.
    • Session hijacking: Impersonation of the user on other websites if session cookies are accessible.
    • Malware distribution: Redirection to malicious websites or drive-by downloads.
    • Phishing attacks: Displaying fake login forms or misleading content within the presentation context.
  • Browser Vulnerabilities: Vulnerabilities in the web browser itself could be exploited by malicious presentation content. While less directly related to reveal.js, it's an accepted risk as stated in the review.
  • User Awareness: Users need to be aware of safe browsing practices and only view presentations from trusted sources. Social engineering attacks could trick users into viewing malicious presentations.

B. reveal.js Presentation (Software System & Container)

• Component: The reveal.js Presentation, consisting of the reveal.js Library and Presentation HTML/CSS/JS.
• Data Flow: The Presentation HTML/CSS/JS loads the reveal.js Library. The library then processes the presentation content and user interactions to render the presentation.
• Security Implications:
  • Cross-Site Scripting (XSS): This is the most significant risk. If presentation authors embed untrusted or unsanitized content (e.g., user-provided data, external iframes, malicious JavaScript) into their presentation HTML, it can lead to XSS vulnerabilities.
    • Impact: Malicious scripts can be injected and executed in the context of users viewing the presentation, leading to the same consequences as listed under "Client-Side Execution Risks" above.
    • Reveal.js Specifics: Reveal.js itself renders user-provided HTML. It does not inherently sanitize input. The responsibility for preventing XSS lies heavily on the presentation creator.
  • Dependency Vulnerabilities (reveal.js Library): reveal.js, like any JavaScript library, relies on dependencies (though it aims to be lightweight, plugins might introduce dependencies). Vulnerabilities in these dependencies could be exploited if not regularly scanned and updated.
    • Impact: Compromise of the reveal.js library functionality, potentially leading to XSS or other vulnerabilities.
  • Plugin Vulnerabilities: Reveal.js has a plugin ecosystem. Plugins, especially community-contributed ones, might introduce vulnerabilities if not properly vetted and maintained.
    • Impact: Similar to dependency vulnerabilities, plugins can introduce XSS, logic flaws, or other security issues.
  • Content Injection: If presentation content is dynamically generated or includes external resources without proper validation, it could be vulnerable to content injection attacks. This is closely related to XSS but emphasizes the source of the untrusted content.

C. Web Server / CDN (Software System & Container & Infrastructure)

• Component: Web Server/CDN hosting reveal.js Library Files and Presentation Files.
• Data Flow: Web browsers request files from the Web Server/CDN.
• Security Implications:
  • Data in Transit Security (HTTPS): Serving reveal.js and presentation content over HTTP (without HTTPS) exposes data in transit to eavesdropping and manipulation (Man-in-the-Middle attacks).
    • Impact: Confidential presentation content could be intercepted. Malicious actors could inject code into the served files, compromising presentations.
    • Mitigation: HTTPS is crucial and assumed as a best practice in the Security Design Review.
  • Web Server Misconfiguration: Misconfigured web servers can introduce vulnerabilities.
    • Impact: Information disclosure, unauthorized access, denial of service.
    • Reveal.js Specifics: Less directly related to reveal.js itself, but the security of the hosting environment is critical.
  • CDN Compromise (If using CDN): If a CDN is compromised, malicious files could be served in place of legitimate reveal.js library or presentation files.
    • Impact: Widespread distribution of compromised presentations, potentially affecting many users.
    • Mitigation: SRI is recommended to mitigate this risk.
  • Access Control to Server/CDN: Unauthorized access to the web server or CDN infrastructure could allow attackers to modify or replace presentation files or the reveal.js library.
    • Impact: Defacement of presentations, distribution of malicious content, denial of service.

D. Build Process (Build Diagram Components)

• Components: Developer, Code Changes, GitHub Repository, GitHub Actions CI, Build & Test, Build Artifacts, Web Server/CDN, Developer Notification.
• Data Flow: Developers commit code changes to the GitHub Repository. GitHub Actions CI triggers the Build & Test process, generating Build Artifacts which are then deployed to the Web Server/CDN.
• Security Implications:
  • Compromised Development Environment: If a developer's machine is compromised, malicious code could be introduced into the reveal.js codebase or presentation files.
    • Impact: Introduction of vulnerabilities or backdoors into reveal.js.
  • Supply Chain Attacks (Dependency Vulnerabilities during Build): Vulnerabilities in dependencies used during the build process (e.g., npm packages) could be exploited to inject malicious code into the build artifacts.
    • Impact: Distribution of compromised reveal.js library.
    • Mitigation: Dependency scanning during the build process is crucial.
  • CI/CD Pipeline Security: Compromised CI/CD pipelines (e.g., GitHub Actions workflows) could be used to inject malicious code into build artifacts or deploy compromised versions of reveal.js.
    • Impact: Distribution of compromised reveal.js library.
    • Mitigation: Secure CI/CD configuration, secret management, access control to workflows.
  • Build Artifact Integrity: If build artifacts are not securely stored and transferred, they could be tampered with before deployment.
    • Impact: Deployment of compromised reveal.js library.
    • Mitigation: Artifact signing and integrity checks.

3. Actionable and Tailored Mitigation Strategies for reveal.js

Based on the identified security implications and the recommended security controls in the Security Design Review, here are actionable and tailored mitigation strategies for reveal.js:

A. For reveal.js Library Developers:

1. Implement and Enforce Content Security Policy (CSP) Headers:

   • Action: Provide clear documentation and examples on how users can configure CSP headers for their reveal.js presentations. Consider providing a default, secure CSP configuration as a starting point.
   • Tailored to reveal.js: Focus CSP directives on restricting script sources, object-src, and frame-ancestors to mitigate XSS risks inherent in user-generated presentation content. Example CSP: default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; font-src 'self'; connect-src 'self'; frame-ancestors 'self'; (This is a starting point and needs to be adjusted based on specific presentation needs and plugin usage).
   • Rationale: CSP is a highly effective browser security mechanism to mitigate XSS by controlling the resources the browser is allowed to load.

2. Promote and Facilitate Subresource Integrity (SRI):

   • Action: Clearly document and encourage users to use SRI when loading reveal.js library files from CDNs or external sources. Provide tools or scripts to easily generate SRI hashes for reveal.js files.
   • Tailored to reveal.js: Since reveal.js is often deployed from CDNs, SRI is crucial to ensure the integrity of the library files fetched by users' browsers.
   • Rationale: SRI ensures that files fetched from external sources have not been tampered with, protecting against CDN compromise or Man-in-the-Middle attacks.

3. Regular Dependency Scanning and Updates:

   • Action: Implement automated dependency scanning in the development pipeline (e.g., using GitHub Dependabot or similar tools). Regularly update dependencies to address known vulnerabilities.
   • Tailored to reveal.js: Focus on scanning both core reveal.js dependencies and dependencies of any officially maintained plugins.
   • Rationale: Proactively address known vulnerabilities in third-party libraries to reduce the attack surface of reveal.js.

4. Automated Security Testing (SAST/DAST) in Development Pipeline:

   • Action: Integrate SAST and DAST tools into the GitHub Actions CI pipeline. Focus SAST on identifying potential XSS vulnerabilities in the reveal.js codebase itself (though less likely in the core framework, plugins are a higher risk). DAST might be less directly applicable to the library itself, but could be used to test example presentations for common web vulnerabilities.
   • Tailored to reveal.js: Prioritize SAST rules that detect common JavaScript security vulnerabilities and XSS patterns.
   • Rationale: Identify potential vulnerabilities early in the development lifecycle, before they are released to users.

5. Security Audits and Code Reviews (Focus on Plugins):

   • Action: Conduct periodic security audits of the reveal.js codebase, especially when major changes are introduced or new plugins are added. Implement mandatory code reviews for all contributions, with a focus on security aspects.
   • Tailored to reveal.js: Pay special attention to the security of plugins, as they are more likely to introduce vulnerabilities due to wider community contributions and potentially less rigorous security scrutiny.
   • Rationale: Proactive security assessments and code reviews help identify and mitigate vulnerabilities that might be missed by automated tools.

6. Promote Secure Plugin Development Guidelines:

   • Action: Develop and publish clear guidelines for plugin developers on secure coding practices, especially regarding input validation, output encoding, and avoiding common web security vulnerabilities.
   • Tailored to reveal.js: Focus guidelines on the specific context of reveal.js plugins and the risks associated with dynamically adding content and functionality to presentations.
   • Rationale: Empower plugin developers to create secure plugins, reducing the overall attack surface of the reveal.js ecosystem.

B. For Users Creating reveal.js Presentations:

1. Strict Input Validation and Output Encoding:

   • Action: When embedding any external content or user-provided data into presentations, rigorously validate and sanitize input and properly encode output. Avoid directly embedding untrusted HTML or JavaScript.
   • Tailored to reveal.js: This is the most critical recommendation for users. Emphasize that reveal.js itself does not sanitize user-provided HTML, and XSS prevention is their direct responsibility.
   • Rationale: Prevent XSS vulnerabilities by ensuring that untrusted data is not interpreted as executable code by the browser.

2. Implement Content Security Policy (CSP):

   • Action: Configure CSP headers for the web server serving the presentation to restrict the sources of content the browser is allowed to load.
   • Tailored to reveal.js: Provide clear instructions and examples on how to set CSP headers for common web servers and hosting environments used with reveal.js.
   • Rationale: CSP provides a strong defense-in-depth mechanism against XSS, even if input validation is missed.

3. Use Subresource Integrity (SRI) for External Resources:

   • Action: When including reveal.js library files or other external resources (e.g., CDN hosted plugins, libraries) in presentation HTML, use SRI attributes to ensure integrity.
   • Tailored to reveal.js: Especially important when using CDN hosted reveal.js library files.
   • Rationale: Protect against compromised CDNs or Man-in-the-Middle attacks by verifying the integrity of external resources.

4. Regularly Update reveal.js Library and Plugins:

   • Action: Keep the reveal.js library and any used plugins updated to the latest versions to benefit from security patches and bug fixes.
   • Tailored to reveal.js: Monitor reveal.js releases and plugin updates for security announcements.
   • Rationale: Address known vulnerabilities by staying up-to-date with the latest versions.

5. Host Presentations on HTTPS:

   • Action: Always serve reveal.js presentations over HTTPS to encrypt data in transit.
   • Tailored to reveal.js: This is a fundamental web security best practice and essential for protecting presentation content and user sessions.
   • Rationale: Prevent eavesdropping and Man-in-the-Middle attacks.

6. Minimize Use of External and Untrusted Content:

   • Action: Reduce the attack surface by minimizing the inclusion of external resources (iframes, external scripts, etc.) and avoiding embedding content from untrusted sources.
   • Tailored to reveal.js: Be cautious when embedding content from third-party websites or user-generated content within presentations.
   • Rationale: Limit the potential for introducing vulnerabilities through external dependencies or untrusted sources.

By implementing these tailored mitigation strategies, both the reveal.js development team and users can significantly enhance the security posture of reveal.js presentations and reduce the risks associated with its use. These recommendations are specific to the nature of reveal.js as a client-side presentation framework and address the key security concerns identified in the analysis.