mitigations.md

Mitigation Strategies Analysis for ankane/searchkick

Mitigation Strategy: Strict search_data Definition

• Mitigation Strategy: Define the search_data method with extreme precision, whitelisting only necessary fields.

• Description:

  1. Locate Models: In your Rails application, find all models using the searchkick gem.
  2. Review/Create search_data: For each model, carefully examine or create the search_data method.
  3. Whitelist Fields: Explicitly list only the fields absolutely required for search. Do not use attributes or similar methods that include all fields.
  4. Data Sensitivity: Assess the sensitivity of each field. Exclude private data, API keys, internal IDs, or anything not intended for public search.
  5. Nested Objects: If indexing data from associated models, include only necessary fields from those associations (e.g., category.name, not the entire category object).
  6. Regular Review: Schedule regular reviews (e.g., quarterly) of search_data methods to maintain accuracy and security.

• Threats Mitigated:

  • Data Exposure (High Severity): Prevents sensitive data indexing, protecting it from unauthorized access via search.
  • Information Leakage (Medium Severity): Reduces unintentional exposure of internal data or metadata.
  • Enumeration Attacks (Medium Severity): Limits indexed fields, hindering attackers from enumerating internal IDs or other data.

• Impact:

  • Data Exposure: Significantly reduces risk (High impact).
  • Information Leakage: Moderately reduces risk (Medium impact).
  • Enumeration Attacks: Moderately reduces risk (Medium impact).

• Currently Implemented:

  • Example: app/models/product.rb - search_data includes only name, description, and public_category.
  • Example: app/models/user.rb - search_data includes only username and public_profile.

• Missing Implementation:

  • Example: app/models/order.rb - Uses attributes in search_data, exposing all order details. Needs refactoring to whitelist fields.
  • Example: app/models/internal_document.rb - searchkick enabled, but no search_data defined (indexes all attributes by default). Requires immediate attention.

Mitigation Strategy: Field-Level Permissions within search_data

• Mitigation Strategy: Conditionally include data in the search_data method based on user permissions.

• Description:

  1. Identify Sensitive Fields: In Searchkick-enabled models, identify fields searchable only by specific users/roles.
  2. Access Current User: Access the currently logged-in user within the search_data method (e.g., using Current.user).
  3. Conditional Inclusion: Use conditional logic (if, unless) within search_data to include sensitive fields only if the user has the required permissions.
  4. Example:

     def search_data
       data = { name: name, description: description }
       data[:internal_notes] = internal_notes if Current.user&.admin?
       data
     end

  5. Test Thoroughly: Write tests to verify the conditional logic and ensure sensitive fields are indexed only for authorized users.

• Threats Mitigated:

  • Data Exposure (High Severity): Prevents unauthorized users from searching and accessing restricted data.
  • Privilege Escalation (Medium Severity): Reduces the risk of users accessing information beyond their authorization.

• Impact:

  • Data Exposure: Significantly reduces risk (High impact).
  • Privilege Escalation: Moderately reduces risk (Medium impact).

• Currently Implemented:

  • Example: app/models/product.rb - internal_notes indexed only for admin users.

• Missing Implementation:

  • Example: app/models/report.rb - confidential_summary indexed for all users. Update to index only for users with specific permissions (e.g., "report_viewer" role).

Mitigation Strategy: Query Complexity Limits (using body_options)

• Mitigation Strategy: Limit query complexity and resource consumption using Searchkick's body_options.

• Description:

  1. Identify Search Entry Points: Determine where users initiate searches (e.g., controller actions).
  2. Use body_options: When calling Model.search, use the body_options parameter.
  3. size Limit: Set a reasonable maximum number of results (size). Avoid unlimited results.
  4. timeout Limit: Set a timeout (e.g., 1s, 500ms) to prevent queries from running indefinitely.
  5. Example:

     Product.search("query", body_options: { size: 50, timeout: "1s" })

  6. Monitor Performance: Regularly monitor Elasticsearch performance to identify slow or resource-intensive queries.

• Threats Mitigated:

  • Denial of Service (DoS) (High Severity): Prevents attackers from overwhelming Elasticsearch with complex queries.
  • Resource Exhaustion (Medium Severity): Reduces the risk of slow queries consuming excessive resources.

• Impact:

  • Denial of Service (DoS): Significantly reduces risk (High impact).
  • Resource Exhaustion: Moderately reduces risk (Medium impact).

• Currently Implemented:

  • Example: app/controllers/products_controller.rb - search action uses body_options: { size: 100, timeout: "2s" }.

• Missing Implementation:

  • Example: app/controllers/reports_controller.rb - search action doesn't use body_options. Needs size and timeout limits.

Mitigation Strategy: Avoid Raw Queries / Use Parameterized Queries (Within Searchkick)

• Mitigation Strategy: Prioritize Searchkick's API; if raw queries are unavoidable, use parameterized queries.

• Description:

  1. Prefer Searchkick Methods: Whenever possible, use Searchkick's built-in methods (e.g., where, order, aggs) instead of constructing raw Elasticsearch queries as strings.
  2. Parameterized Queries (If Necessary): If you must use raw queries within body_options or other advanced features, use parameterized queries (placeholders) instead of string concatenation to prevent injection. Consult Elasticsearch documentation for the correct syntax.
  3. Review Existing Code: Examine your codebase for any instances where raw Elasticsearch queries are constructed, especially within body_options or custom aggregations. Refactor these to use Searchkick's API or parameterized queries.

• Threats Mitigated:

  • Elasticsearch Injection (Low Severity, but potentially High Impact): Reduces the risk of attackers injecting malicious code into Elasticsearch queries. This is less likely with proper Searchkick usage but crucial if using raw queries.

• Impact:

  • Elasticsearch Injection: Significantly reduces risk (High impact, low probability with correct Searchkick API usage).

• Currently Implemented:

  • Example: Most search functionality uses Searchkick's built-in methods.

• Missing Implementation:

  • Example: A custom aggregation in app/models/product.rb uses string concatenation to build a raw query. This needs to be refactored to use parameterized queries or Searchkick's aggregation API.

Mitigation Strategy: Input Sanitization (Influencing Searchkick Queries)

• Mitigation Strategy: Validate and sanitize user input that is passed into Searchkick methods.

• Description:

  1. Identify Input Points: Determine all places where user input influences Searchkick queries (search forms, API parameters).
  2. Length Limits: Restrict the maximum length of search terms to prevent overly long queries.
  3. Character Whitelisting: Define a whitelist of allowed characters for search terms. Consider alphanumeric characters, spaces, and limited punctuation.
  4. Regular Expressions: Use regular expressions to validate the format of search terms.
  5. Example (Length Limit):

     query = params[:q].presence || ""
     query = query[0, 100] # Limit to 100 characters

  6. Example (Character Whitelisting - Conceptual):

     # Only allow alphanumeric characters and spaces
     if query =~ /^[a-zA-Z0-9\s]+$/
       # Proceed with search using Searchkick
     else
       # Handle invalid input
     end

  7. Test Thoroughly: Write tests to verify input validation and sanitization.

• Threats Mitigated:

  • Denial of Service (DoS) (Medium Severity): Prevents crafted inputs from creating overly complex queries.
  • Elasticsearch Injection (Low Severity, but potentially High Impact): Provides an additional layer of defense, especially if custom query logic is used.
  • Cross-Site Scripting (XSS) (Low Severity in this context): While Searchkick handles basic escaping, input sanitization adds defense.

• Impact:

  • Denial of Service (DoS): Moderately reduces risk (Medium impact).
  • Elasticsearch Injection: Provides additional risk reduction (High impact, low probability).
  • Cross-Site Scripting (XSS): Small additional risk reduction (Low impact).

• Currently Implemented:

  • Example: app/controllers/products_controller.rb - search action limits query length.

• Missing Implementation:

  • Example: No character whitelisting or regex validation for search terms.
  • Example: app/controllers/reports_controller.rb - search action lacks input sanitization.

Mitigation Strategy: Keep Searchkick Updated

• Mitigation Strategy: Regularly update the Searchkick gem to the latest stable version.

• Description:

  1. Use Bundler: Use Bundler (Gemfile) to manage your Ruby dependencies.
  2. Regular Updates: Run bundle update searchkick periodically (e.g., monthly) to update Searchkick.
  3. Version Constraints: Use pessimistic version constraints (e.g., gem 'searchkick', '~> 5.0') in your Gemfile.
  4. Changelog Review: Before updating, review the Searchkick changelog for security fixes.
  5. Test After Updates: Thoroughly test your application after updating Searchkick.

• Threats Mitigated:

  • Known Vulnerabilities (Variable Severity): Protects against known vulnerabilities in the Searchkick library itself.

• Impact:

  • Known Vulnerabilities: Significantly reduces risk (High impact).

• Currently Implemented:

  • Example: Gemfile uses pessimistic version constraints for searchkick.

• Missing Implementation:

  • Example: Updates are not performed regularly; the project is several minor versions behind.