Skip to content

Latest commit

 

History

History
149 lines (113 loc) · 13.2 KB

mitigations.md

File metadata and controls

149 lines (113 loc) · 13.2 KB

Mitigation Strategies Analysis for bitwarden/server

Mitigation Strategy: Parameterized Queries and ORM Enforcement

Mitigation Strategy: Enforce the exclusive use of parameterized queries (provided by the ORM, Entity Framework Core) for all database interactions on the server. Prohibit any direct string concatenation or interpolation when constructing SQL queries within the server's code.

  • Description:

    1. Code Review Policy (Server-Side): Establish a mandatory code review policy for all server-side code that specifically checks for any instances of raw SQL query construction using string manipulation.
    2. Static Analysis (Server-Side): Integrate a static analysis tool (e.g., Roslyn analyzers for C#) into the server's build pipeline. Configure the tool to flag any server-side code that builds SQL queries using string concatenation or interpolation.
    3. Training (Server-Side Developers): Provide server-side developers with training on secure coding practices, emphasizing the dangers of SQL injection and the correct usage of parameterized queries with the ORM.
    4. ORM Usage (Server-Side): Utilize the Entity Framework Core's features for building queries (e.g., LINQ to Entities) which inherently use parameterized queries. Avoid FromSqlRaw or ExecuteSqlRaw on the server unless absolutely necessary, and if used, ensure parameters are always used.
    5. Documentation (Server-Side): Clearly document the policy against raw SQL construction and the proper use of the ORM in the project's server-side coding standards.

  • Threats Mitigated:

    • SQL Injection (Critical): Prevents attackers from injecting malicious SQL code into database queries executed by the server, which could lead to data breaches, data modification, or even server compromise.
    • Data Exposure (Critical): Reduces the risk of unintended data exposure through error messages or manipulated queries on the server.

  • Impact:

    • SQL Injection: Risk reduction: Very High (near elimination if implemented comprehensively on the server).
    • Data Exposure: Risk reduction: High.

  • Currently Implemented (Educated Guess): Likely implemented to a large extent on the server. Bitwarden uses Entity Framework Core, which encourages parameterized queries. However, thorough code review and static analysis are crucial to ensure consistent enforcement on the server.

  • Missing Implementation (Educated Guess): Potential areas for improvement on the server:

    • Comprehensive Static Analysis (Server-Side): Ensuring all server-side code paths are covered by static analysis rules.
    • Strict Policy Enforcement (Server-Side): A formal, documented policy with automated checks and mandatory code reviews for server code.
    • Auditing of FromSqlRaw/ExecuteSqlRaw Usage (Server-Side): If these methods are used anywhere on the server, they need extremely rigorous auditing and justification.

Mitigation Strategy: Input Validation and Sanitization (API Layer - Server-Side)

Mitigation Strategy: Implement strict input validation and sanitization at the server's API layer for all incoming data, before it's processed or passed to any other part of the server application.

  • Description:

    1. Define Input Schemas (Server-Side): For each API endpoint on the server, define a clear schema that specifies the expected data types, formats, lengths, and allowed values for each input parameter.
    2. Validation Library (Server-Side): Use a robust validation library (e.g., FluentValidation for .NET) on the server to enforce the defined schemas.
    3. Whitelist Approach (Server-Side): Prefer a whitelist approach to validation on the server, where only explicitly allowed values are accepted.
    4. Data Type Validation (Server-Side): Validate that data conforms to the expected data type on the server.
    5. Length Restrictions (Server-Side): Enforce appropriate length restrictions on string inputs on the server.
    6. Format Validation (Server-Side): Validate the format of specific data types on the server.
    7. Sanitization (Server-Side): If necessary, sanitize input data on the server. Validation is generally preferred. Sanitization should be context-specific.
    8. Error Handling (Server-Side): Provide clear and informative error messages to the client when validation fails on the server, but avoid revealing sensitive information.

  • Threats Mitigated:

    • Cross-Site Scripting (XSS) (High): Prevents malicious scripts from being injected through API requests (if API output is rendered in a web UI). This is relevant if the server generates any HTML.
    • SQL Injection (Medium): Provides an additional layer of defense against SQL injection on the server.
    • NoSQL Injection (Medium): If any NoSQL databases are used by the server, this helps prevent injection.
    • Command Injection (High): Prevents attackers from injecting operating system commands through API requests to the server.
    • Denial of Service (DoS) (Medium): Length restrictions and format validation on the server can help prevent some DoS attacks.
    • Business Logic Attacks (Medium): Validating input against expected business rules on the server can prevent exploitation of flaws.

  • Impact:

    • XSS, Command Injection: Risk reduction: High.
    • SQL Injection, NoSQL Injection: Risk reduction: Medium (secondary defense).
    • DoS, Business Logic Attacks: Risk reduction: Medium.

  • Currently Implemented (Educated Guess): Likely implemented to some degree on the server. Modern API frameworks often provide built-in validation.

  • Missing Implementation (Educated Guess):

    • Comprehensive Schema Definition (Server-Side): Ensuring every server API endpoint has a clearly defined and enforced input schema.
    • Centralized Validation Logic (Server-Side): Using a consistent validation library and approach across the entire server API.
    • Regular Review of Validation Rules (Server-Side): Periodically reviewing and updating validation rules on the server.

Mitigation Strategy: Secure Configuration Management (Server-Side)

Mitigation Strategy: Store all sensitive configuration data used by the server (database connection strings, API keys, encryption keys, etc.) securely, outside of the server application's codebase.

  • Description:

    1. Avoid Hardcoding (Server-Side): Never hardcode secrets directly into the server's source code.
    2. Environment Variables (Server-Side): Use environment variables to store secrets, especially in containerized environments.
    3. Secrets Management Service (Server-Side): Utilize a dedicated secrets management service.
    4. Encrypted Configuration Files (Server-Side): If using configuration files on the server, encrypt them.
    5. Access Control (Server-Side): Restrict access to secrets to only the necessary server services and users.
    6. Rotation (Server-Side): Regularly rotate secrets used by the server.

  • Threats Mitigated:

    • Credential Exposure (Critical): Prevents attackers from gaining access to sensitive credentials if the server's codebase is compromised.
    • Unauthorized Access (Critical): Reduces the risk of unauthorized access to databases, APIs, and other resources by the server.

  • Impact:

    • Credential Exposure, Unauthorized Access: Risk reduction: Very High.

  • Currently Implemented (Educated Guess): Highly likely to be implemented on the server.

  • Missing Implementation (Educated Guess):

    • Consistent Use of Secrets Management (Server-Side): Ensuring all server secrets are managed through the chosen solution.
    • Automated Secret Rotation (Server-Side): Implementing automated secret rotation for the server.
    • Auditing of Secret Access (Server-Side): Regularly auditing access to secrets used by the server.

Mitigation Strategy: Rate Limiting (API Layer - Server-Side)

Mitigation Strategy: Implement robust rate limiting on all server API endpoints, especially those related to authentication and sensitive data access.

  • Description:

    1. Identify Critical Endpoints (Server-Side): Identify server API endpoints that are particularly sensitive or vulnerable.
    2. Choose a Rate Limiting Strategy (Server-Side): Select an appropriate rate limiting strategy.
    3. Set Appropriate Limits (Server-Side): Define rate limits based on expected usage patterns of each server endpoint.
    4. Implement Rate Limiting Middleware (Server-Side): Use a rate limiting middleware or library on the server.
    5. Informative Responses (Server-Side): When a rate limit is exceeded, return a clear HTTP status code (429) with a Retry-After header.
    6. Monitoring (Server-Side): Monitor rate limiting activity on the server.
    7. IP Address and User-Based Limits (Server-Side): Consider rate limiting based on both IP address and user ID on the server.

  • Threats Mitigated:

    • Brute-Force Attacks (High): Limits the number of login attempts or password reset requests handled by the server.
    • Denial of Service (DoS) (Medium): Helps prevent attackers from overwhelming the server.
    • Credential Stuffing (High): Makes it harder for attackers to use stolen credentials against the server.
    • Automated Scraping (Medium): Can limit the rate at which attackers can scrape data from the server's API.

  • Impact:

    • Brute-Force Attacks, Credential Stuffing: Risk reduction: High.
    • DoS, Automated Scraping: Risk reduction: Medium.

  • Currently Implemented (Educated Guess): Likely implemented, at least for authentication-related endpoints on the server.

  • Missing Implementation (Educated Guess):

    • Comprehensive Coverage (Server-Side): Ensuring all relevant server API endpoints are protected.
    • Fine-Grained Limits (Server-Side): Using different rate limits for different server endpoints and user roles.
    • Dynamic Rate Limiting (Server-Side): Adjusting rate limits dynamically based on server load.
    • Monitoring and Alerting (Server-Side): Setting up monitoring and alerting for rate limiting events on the server.

Mitigation Strategy: Feature-Specific Security Reviews (Example: Sharing - Server-Side)

Mitigation Strategy: Conduct dedicated security reviews and penetration testing for the server-side implementation of the "sharing" feature.

  • Description:

    1. Threat Modeling (Server-Side): Perform a threat modeling exercise specifically for the server-side aspects of the sharing feature.
    2. Code Review (Server-Side): Conduct a focused code review of the server-side sharing-related code.
    3. Penetration Testing (Server-Side): Engage in penetration testing that specifically targets the server-side logic of the sharing feature.
    4. Input Validation (Server-Side): Ensure that all input related to sharing is strictly validated on the server.
    5. Access Control Enforcement (Server-Side): Verify that access control checks are performed correctly on the server at every stage of the sharing process.
    6. Encryption (Server-Side): Confirm that shared data is properly encrypted by the server, both in transit and at rest.
    7. Auditing (Server-Side): Implement detailed auditing on the server of all sharing-related actions.

  • Threats Mitigated:

    • Unauthorized Data Access (Critical): Prevents unauthorized users from accessing shared items via vulnerabilities on the server.
    • Privilege Escalation (High): Prevents users from gaining higher privileges than they should have on shared items via the server.
    • Data Modification (High): Prevents unauthorized modification of shared items via the server.
    • Data Leakage (High): Reduces the risk of shared data being leaked from the server.
    • Broken Access Control (Critical): Addresses vulnerabilities related to incorrect access control checks on the server.

  • Impact:

    • Unauthorized Data Access, Privilege Escalation, Data Modification, Data Leakage, Broken Access Control: Risk reduction: High.

  • Currently Implemented (Educated Guess): Likely implemented to a significant extent on the server.

  • Missing Implementation (Educated Guess):

    • Regular, Dedicated Penetration Testing (Server-Side): Ensuring regular penetration testing of the server-side sharing logic.
    • Formal Threat Modeling (Server-Side): Conducting a formal threat modeling exercise specifically for the server-side aspects of sharing.
    • Edge Case Testing (Server-Side): Thoroughly testing edge cases on the server.