Skip to content

Latest commit

 

History

History
193 lines (146 loc) · 20.1 KB

sec-design-deep-analysis.md

File metadata and controls

193 lines (146 loc) · 20.1 KB

Okay, let's perform a deep security analysis of CasaOS based on the provided design review.

1. Objective, Scope, and Methodology

  • Objective: To conduct a thorough security analysis of CasaOS's key components, identify potential vulnerabilities, assess their impact, and propose actionable mitigation strategies. The analysis will focus on the architecture, data flow, and security controls described in the design review, and infer additional details from the project's nature (home cloud system). The goal is to improve CasaOS's security posture, focusing on practical risks for home users.

  • Scope:

    • CasaOS core components (Web Application, API Service, System Service, Database).
    • Docker Engine and Application Container interactions.
    • User authentication and authorization mechanisms.
    • Data storage and handling.
    • Build and deployment processes (GitHub Actions).
    • Interaction with external services (Docker Hub).
    • The deployment scenario is bare-metal.

  • Methodology:

    1. Component Decomposition: Analyze each component identified in the C4 diagrams and descriptions.
    2. Threat Modeling: Identify potential threats to each component based on its function, interactions, and data handled. We'll use a combination of STRIDE (Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege) and practical attack scenarios relevant to home cloud environments.
    3. Vulnerability Analysis: Assess the likelihood and impact of each identified threat, considering existing and recommended security controls.
    4. Mitigation Recommendations: Propose specific, actionable steps to mitigate identified vulnerabilities, tailored to CasaOS's architecture and target audience.
    5. Inference: Since we don't have direct access to the codebase, we'll make informed inferences about the architecture and potential vulnerabilities based on the design review, common practices, and the nature of the project.

2. Security Implications of Key Components

Let's break down the security implications of each component, applying the STRIDE threat model and considering practical attack scenarios:

  • Web Application (UI)

    • Threats:

      • Cross-Site Scripting (XSS): If user input (e.g., application names, configuration settings) is not properly sanitized, an attacker could inject malicious JavaScript code, potentially stealing cookies, redirecting users, or defacing the interface. (Tampering, Information Disclosure)
      • Cross-Site Request Forgery (CSRF): An attacker could trick a logged-in user into performing unintended actions (e.g., changing settings, deleting data) by sending a malicious request from another website. (Tampering, Elevation of Privilege)
      • Session Hijacking: If session management is weak (e.g., predictable session IDs, lack of HTTPS), an attacker could hijack a user's session and gain unauthorized access. (Spoofing, Elevation of Privilege)
      • Clickjacking: An attacker could overlay the CasaOS UI with an invisible iframe, tricking users into clicking on malicious elements. (Tampering)
      • Information Disclosure: Error messages or debug information displayed in the UI could reveal sensitive details about the system's internal workings. (Information Disclosure)

    • Vulnerabilities: Likelihood is medium-high (common web app vulnerabilities), impact is medium-high (depending on the compromised functionality).

    • Mitigation:

      • Strict Input Validation: Implement robust server-side input validation for all user-supplied data, using a whitelist approach (allow only known-good characters) rather than a blacklist. Client-side validation is good for UX but insufficient for security.
      • Output Encoding: Properly encode output data displayed in the UI to prevent XSS. Use context-specific encoding (e.g., HTML encoding, JavaScript encoding).
      • CSRF Protection: Implement CSRF tokens (synchronizer token pattern) on all state-changing requests.
      • Secure Session Management: Use strong, randomly generated session IDs, set the HttpOnly and Secure flags on cookies, and implement appropriate session timeouts. Ensure all communication is over HTTPS.
      • Content Security Policy (CSP): Implement a strong CSP to mitigate XSS and other code injection attacks. This is a crucial defense-in-depth measure.
      • X-Frame-Options: Set the X-Frame-Options header to DENY or SAMEORIGIN to prevent clickjacking.
      • Error Handling: Implement proper error handling that does not reveal sensitive information to the user. Log detailed error information server-side.

  • API Service (Backend)

    • Threats:

      • Injection Attacks (SQLi, Command Injection): If user input is used to construct SQL queries or shell commands without proper sanitization, an attacker could inject malicious code, potentially gaining access to the database or the underlying operating system. (Tampering, Information Disclosure, Elevation of Privilege)
      • Authentication Bypass: Weaknesses in the authentication logic could allow attackers to bypass authentication and gain unauthorized access to API endpoints. (Spoofing, Elevation of Privilege)
      • Authorization Bypass: Flaws in authorization checks could allow users to access resources or perform actions they are not permitted to. (Elevation of Privilege)
      • Denial of Service (DoS): An attacker could flood the API with requests, overwhelming the server and making it unavailable to legitimate users. (Denial of Service)
      • Information Disclosure: API responses could leak sensitive information, such as internal server details, API keys, or user data. (Information Disclosure)
      • Insecure Deserialization: If the API deserializes untrusted data, an attacker could exploit vulnerabilities in the deserialization process to execute arbitrary code. (Tampering, Elevation of Privilege)

    • Vulnerabilities: Likelihood is high (APIs are common attack vectors), impact is high (direct access to backend functionality).

    • Mitigation:

      • Input Validation: As with the UI, rigorous server-side input validation is essential for all API endpoints. Use a whitelist approach and validate data types, lengths, and formats.
      • Parameterized Queries (Prepared Statements): Use parameterized queries or prepared statements to prevent SQL injection. Never concatenate user input directly into SQL queries.
      • Safe Command Execution: Avoid using shell commands if possible. If necessary, use a safe API that prevents command injection (e.g., exec.Command in Go with separate arguments).
      • Strong Authentication: Implement robust authentication using strong password hashing algorithms (bcrypt, Argon2) and secure session management (if applicable). Consider supporting API keys for programmatic access, and ensure they are stored securely.
      • Role-Based Access Control (RBAC): Implement RBAC to restrict user access to specific API endpoints and resources based on their roles and permissions.
      • Rate Limiting: Implement rate limiting to prevent DoS attacks. Limit the number of requests a user can make within a specific time period.
      • Secure Error Handling: Return generic error messages to the client and log detailed error information server-side.
      • Secure Deserialization: If deserialization is necessary, use a safe library and validate the data before deserializing it. Avoid deserializing untrusted data if possible.
      • API Gateway (Consideration): For more complex deployments, consider using an API gateway to handle authentication, authorization, rate limiting, and other security concerns.

  • Docker Engine

    • Threats:

      • Container Escape: A vulnerability in Docker or the underlying kernel could allow an attacker to escape from a container and gain access to the host operating system. (Elevation of Privilege)
      • Denial of Service (DoS): A compromised or malicious container could consume excessive resources (CPU, memory, network), impacting other containers or the host system. (Denial of Service)
      • Image Vulnerabilities: Vulnerabilities in the base images or application code within containers could be exploited by attackers. (Tampering, Information Disclosure, Elevation of Privilege)
      • Docker Socket Exposure: If the Docker socket (/var/run/docker.sock) is exposed to a container or network, it grants full control over the Docker daemon, leading to complete system compromise. (Elevation of Privilege)

    • Vulnerabilities: Likelihood is medium (depends on Docker version and container configuration), impact is high (potential host compromise).

    • Mitigation:

      • Keep Docker Updated: Regularly update the Docker Engine to the latest version to patch security vulnerabilities.
      • Use Non-Root Users: Run containers as non-root users whenever possible. This limits the damage an attacker can do if they compromise a container.
      • Limit Container Capabilities: Use Docker's capabilities mechanism to restrict the privileges of containers. Grant only the necessary capabilities.
      • Resource Limits: Set resource limits (CPU, memory) for containers to prevent DoS attacks.
      • Read-Only Root Filesystem: Mount the container's root filesystem as read-only whenever possible to prevent attackers from modifying system files.
      • Vulnerability Scanning: Use a vulnerability scanner (e.g., Trivy, Clair, Anchore) to scan Docker images for known vulnerabilities before deploying them. Integrate this into the CI/CD pipeline.
      • Secure Docker Socket: Never expose the Docker socket directly to containers or untrusted networks. If necessary, use a secure proxy or the Docker API over TLS.
      • AppArmor/Seccomp: Utilize AppArmor or Seccomp profiles to restrict container capabilities at the kernel level, providing an additional layer of defense.
      • Docker Content Trust: Enable Docker Content Trust to ensure that only signed and verified images are pulled and run.

  • Application Containers (Various Apps)

    • Threats: These are highly dependent on the specific application running within the container. All the threats listed for the Web Application and API Service could apply to applications running within containers. Additionally:

      • Compromised Third-Party Images: Using images from untrusted sources or images that have not been updated could introduce vulnerabilities. (Tampering, Information Disclosure, Elevation of Privilege)
      • Insecure Application Configuration: Misconfigured applications within containers could expose sensitive data or allow unauthorized access. (Information Disclosure, Elevation of Privilege)

    • Vulnerabilities: Likelihood is high (depends on the application and image source), impact varies widely.

    • Mitigation:

      • Use Official Images: Prefer official images from trusted sources (e.g., Docker Hub official images) whenever possible.
      • Regularly Update Images: Keep container images updated to patch vulnerabilities. Automate this process if possible.
      • Vulnerability Scanning: Scan all images for vulnerabilities before deployment.
      • Secure Application Configuration: Follow security best practices for configuring the specific applications running within containers. Use environment variables for sensitive configuration data.
      • Least Privilege: Run applications within containers with the least privilege necessary.
      • Network Segmentation: Use Docker networks to isolate containers from each other and from the host network. Limit network access to only what is required.

  • System Service (OS Level)

    • Threats:

      • OS Vulnerabilities: Unpatched vulnerabilities in the underlying operating system could be exploited by attackers. (Tampering, Information Disclosure, Elevation of Privilege)
      • Misconfiguration: Incorrectly configured system services (e.g., SSH, firewall) could create security weaknesses. (Information Disclosure, Elevation of Privilege)
      • Privilege Escalation: A local attacker could exploit a vulnerability to gain elevated privileges on the system. (Elevation of Privilege)

    • Vulnerabilities: Likelihood is medium (depends on OS and configuration), impact is high (potential full system compromise).

    • Mitigation:

      • Regular System Updates: Keep the operating system updated with the latest security patches. Automate updates if possible.
      • Secure Configuration: Follow security best practices for configuring system services. Disable unnecessary services.
      • Firewall: Configure a firewall to restrict network access to only necessary ports and services. Use a host-based firewall (e.g., iptables, ufw) even if a network firewall is in place.
      • SSH Hardening: If SSH access is required, harden the SSH configuration (e.g., disable root login, use key-based authentication, change the default port).
      • Intrusion Detection System (IDS) (Consideration): For more advanced security, consider deploying a host-based intrusion detection system (HIDS) to monitor for suspicious activity.

  • Database (Settings/Metadata)

    • Threats:

      • SQL Injection: If the database is accessed through an API vulnerable to SQL injection, attackers could gain access to the database contents. (Tampering, Information Disclosure)
      • Unauthorized Access: Weak database credentials or misconfigured access controls could allow unauthorized users to access the database. (Information Disclosure, Tampering)
      • Data Breach: If the database is compromised, sensitive data (e.g., user credentials, configuration settings) could be stolen. (Information Disclosure)

    • Vulnerabilities: Likelihood is medium (depends on database and access methods), impact is high (loss of sensitive data).

    • Mitigation:

      • Strong Passwords: Use strong, unique passwords for the database user accounts.
      • Access Control: Restrict database access to only authorized users and applications. Use the principle of least privilege.
      • Data Encryption at Rest: Encrypt the database files to protect data if the physical storage is compromised.
      • Regular Backups: Implement regular backups of the database to protect against data loss. Store backups securely, preferably offsite.
      • Database Firewall (Consideration): For more advanced security, consider using a database firewall to restrict access to the database based on SQL queries and other criteria.
      • Parameterized Queries: Always use parameterized queries when accessing the database from the API service.

  • GitHub Actions (Build Process)

    • Threats:

      • Compromised Dependencies: Malicious or vulnerable dependencies could be introduced into the build process. (Tampering)
      • Compromised Build Environment: If the GitHub Actions runner is compromised, an attacker could inject malicious code into the build artifacts. (Tampering)
      • Secret Leakage: Secrets (e.g., API keys, credentials) used in the build process could be leaked if not handled securely. (Information Disclosure)

    • Vulnerabilities: Likelihood is low-medium, impact is high (compromised builds).

    • Mitigation:

      • Dependency Management: Use a dependency management tool (e.g., go mod) to track and update dependencies. Regularly audit dependencies for known vulnerabilities.
      • SAST Scanning: Integrate static application security testing (SAST) tools into the GitHub Actions workflow to scan the codebase for vulnerabilities.
      • DAST Scanning: Integrate dynamic application security testing (DAST) to test running application.
      • Secret Management: Use GitHub Actions secrets to securely store sensitive information. Never hardcode secrets in the workflow files or the codebase.
      • Least Privilege: Grant the GitHub Actions workflow only the necessary permissions.
      • Review Workflow Files: Carefully review workflow files for any potential security issues.
      • Use Verified Actions: Prefer using verified actions from trusted sources.
      • Self-Hosted Runners (Consideration): For increased control over the build environment, consider using self-hosted runners instead of GitHub-hosted runners.

3. Actionable Mitigation Strategies (Tailored to CasaOS)

The following are prioritized, actionable mitigation strategies, specifically tailored for CasaOS, considering its target audience and design:

  1. Prioritize Input Validation and Output Encoding: Implement rigorous server-side input validation and context-aware output encoding in both the Web Application (UI) and the API Service. This is the most critical defense against common web vulnerabilities like XSS and injection attacks. Provide clear examples in the documentation for developers contributing to the project.

  2. Implement Robust Authentication and Authorization:

    • Use a strong password hashing algorithm (bcrypt or Argon2).
    • Enforce a strong password policy (minimum length, complexity requirements).
    • Implement secure session management with HttpOnly and Secure cookies.
    • Implement Role-Based Access Control (RBAC) to limit user privileges. Start with a simple model (e.g., "admin" and "user" roles) and expand as needed.

  3. Integrate Docker Image Vulnerability Scanning: Integrate a vulnerability scanner (Trivy is a good, easy-to-use option) into the GitHub Actions CI/CD pipeline. Block builds or deployments if high-severity vulnerabilities are found. Provide clear instructions to users on how to update their application containers.

  4. Provide Secure Configuration Guidance: Create comprehensive documentation that guides users on how to securely configure CasaOS and its applications. This should include:

    • Changing default passwords.
    • Enabling HTTPS.
    • Setting up a firewall.
    • Choosing reputable Docker images.
    • Regularly updating the system and applications.
    • Understanding the risks of self-hosting.

  5. Implement Centralized Logging and Auditing: Implement a centralized logging system to track system events, user activity, and security-relevant events. This is crucial for detecting and responding to security incidents. Consider using a lightweight logging framework that is easy to configure and manage.

  6. Enable Docker Content Trust: Enforce Docker Content Trust to ensure that only signed images from trusted sources are used. This helps prevent the use of tampered or malicious images.

  7. Harden the Base OS: Provide clear instructions to users on how to harden the base operating system (e.g., enabling automatic updates, configuring a firewall, disabling unnecessary services).

  8. Security-Focused Code Reviews: Emphasize security during code reviews. Check for common vulnerabilities, adherence to secure coding practices, and proper handling of sensitive data.

  9. Establish a Vulnerability Disclosure Program: Create a clear process for users and security researchers to report vulnerabilities. Respond to reports promptly and responsibly.

  10. Consider MFA: Offer Multi-Factor Authentication (MFA) as an optional but highly recommended security enhancement. This adds a significant layer of protection against unauthorized access, even if passwords are compromised.

By implementing these mitigation strategies, CasaOS can significantly improve its security posture and protect its users from a wide range of threats. The focus should be on practical, actionable steps that are achievable for a home cloud environment and a community-driven project.