mitigations.md

Mitigation Strategies Analysis for jeremyevans/sequel

Mitigation Strategy: Use Placeholders and Dataset Methods

Description:

1. Identify all user inputs: Determine all points where data from users (or external sources) is used in database queries constructed using Sequel.
2. Replace direct string concatenation: Wherever user input is currently being directly inserted into SQL strings within Sequel code (e.g., within where, select, order, etc.), replace it with Sequel's placeholder syntax.
3. Prefer symbolic placeholders: Use the column: value syntax within Sequel's dataset methods (e.g., dataset.where(username: params[:username])).
4. Use ? placeholders when necessary: If symbolic placeholders aren't suitable, use the ? placeholder syntax (e.g., dataset.where("username = ?", params[:username])).
5. Avoid Sequel.lit: Minimize Sequel.lit. If unavoidable, ensure rigorous input validation before using it, and document the reason clearly within the Sequel-related code.
6. Review all Sequel query construction: Conduct a thorough code review to ensure that all Sequel-based database queries are using placeholders or Sequel's safe dataset methods.
7. Use Virtual Row Blocks with Placeholders: When using Sequel's virtual row blocks, ensure user-supplied values are passed as placeholder arguments to the block, not directly embedded.

Threats Mitigated:

• SQL Injection (Severity: Critical): Attackers can inject malicious SQL code via Sequel if input is not handled correctly within Sequel's API.
• Data Disclosure (Severity: High): Improperly constructed Sequel queries might unintentionally expose sensitive data.
• Data Modification (Severity: High): Attackers could alter or delete data without authorization through manipulated Sequel queries.
• Denial of Service (Severity: Medium): Malicious Sequel queries could overload the database.

Impact:

• SQL Injection: Risk reduced to near zero if implemented correctly within Sequel.
• Data Disclosure: Significantly reduced risk.
• Data Modification: Significantly reduced risk.
• Denial of Service: Some reduction in risk.

Currently Implemented:

• Example:
  • "User authentication queries in models/user.rb use Sequel placeholders."
  • "Product search in controllers/products_controller.rb uses Sequel's filter with symbolic placeholders."

Missing Implementation:

• Example:
  • "Legacy code in lib/legacy_reports.rb uses string concatenation within Sequel calls. Refactor needed."
  • "controllers/admin/users_controller.rb uses Sequel.lit with insufficient validation within a Sequel query. Review and rewrite."

Mitigation Strategy: Whitelist Dynamic Table/Column Names (within Sequel)

Description:

1. Identify dynamic identifiers in Sequel calls: Locate all instances where table or column names are determined by user input and are used within Sequel's API.
2. Create whitelists: For each instance, create a hardcoded list of allowed table and column names.
3. Validate input before Sequel usage: Before passing the user-provided table/column name to any Sequel method, check if it exists in the whitelist.
4. Handle invalid input: If the input is not in the whitelist, reject the request. Do not pass the invalid input to Sequel.
5. Prefer symbols with Sequel: Use symbols (e.g., :users, :name) for table and column names within Sequel calls whenever possible.
6. Review and document: Document the whitelisting logic related to Sequel calls.

Threats Mitigated:

• SQL Injection (Severity: Critical): Prevents attackers from accessing arbitrary tables/columns through Sequel.
• Data Disclosure (Severity: High): Limits access to only authorized tables/columns via Sequel.
• Data Modification (Severity: High): Prevents unauthorized modification via Sequel.

Impact:

• SQL Injection: Significantly reduces risk related to dynamic identifiers used with Sequel.
• Data Disclosure/Modification: Greatly reduces risk.

Currently Implemented:

• Example:
  • "The reporting module (modules/reporting.rb) uses a whitelist for allowed report types before passing them to Sequel."
  • "Dynamic sorting in controllers/products_controller.rb validates the sort column before using it in a Sequel order call."

Missing Implementation:

• Example:
  • "User profile editing (controllers/users_controller.rb) allows specifying fields to update, but this is not validated before being used in a Sequel update call."

Mitigation Strategy: Avoid/Sanitize Raw SQL within Sequel.[]

Description:

1. Minimize raw SQL within Sequel: Prioritize Sequel's dataset methods. Raw SQL within Sequel.[] or DB.fetch should be a last resort.
2. Justify and document: If raw SQL is unavoidable within Sequel, clearly document the reason.
3. Use parameterized queries (within raw SQL): Even within Sequel.[], always use parameterized queries (placeholders) to handle user input. The syntax depends on the database adapter, but Sequel passes this through.
4. Code review: Any code using Sequel.[] or DB.fetch should be rigorously reviewed, focusing on potential SQL injection within the raw SQL string.
5. Consider Sequel alternatives: Explore all Sequel features before resorting to raw SQL within Sequel.[].

Threats Mitigated:

• SQL Injection (Severity: Critical): Directly addresses the highest risk associated with using raw SQL through Sequel.
• Data Disclosure (Severity: High): Reduces risk.
• Data Modification (Severity: High): Reduces risk.
• Denial of Service (Severity: Medium): Reduces risk.

Impact:

• SQL Injection: Significantly reduces risk if parameterized queries are used correctly within the raw SQL passed to Sequel. Eliminates risk if raw SQL within Sequel is avoided.
• Data Disclosure/Modification/DoS: Similar impact.

Currently Implemented:

• Example:
  • "The core application logic avoids raw SQL within Sequel calls."
  • "A database-specific optimization in lib/performance_tweaks.rb uses parameterized raw SQL within DB.fetch, and the reason is documented."

Missing Implementation:

• Example:
  • "Older parts of the application, in lib/legacy, use raw SQL within Sequel.[] without parameterization. Refactor needed."
  • "No formal policy specifically addresses the use of raw SQL within Sequel calls."

Mitigation Strategy: Secure Deserialization (Sequel Plugins)

Description:

1. Identify Sequel plugin deserialization: Determine all places where Sequel plugins are used to deserialize data (e.g., JSON, YAML, or custom serialization plugins).
2. Use safe libraries (within the plugin context): Ensure that the Sequel plugins themselves, or the libraries they rely on, use secure deserialization methods. If you're using a custom plugin, ensure it uses safe methods.
3. Validate after deserialization (by Sequel): After Sequel (or its plugin) deserializes data, rigorously validate the resulting data structure and contents.
4. Consider alternatives to Sequel-based serialization: If possible, avoid storing complex serialized data that needs to be handled by Sequel.
5. Keep Sequel and plugins updated: Regularly update Sequel and all related plugins to patch vulnerabilities.

Threats Mitigated:

• Remote Code Execution (Severity: Critical): Unsafe deserialization by Sequel or its plugins can lead to RCE.
• Data Tampering (Severity: High): Attackers could modify serialized data.

Impact:

• Remote Code Execution: Significantly reduces risk if safe deserialization practices are followed within the Sequel plugin context.
• Data Tampering: Reduces risk through validation after Sequel deserializes.

Currently Implemented:

• Example:
  • "The application uses the pg_json Sequel extension, and we validate the data after retrieval."
  • "Custom Sequel plugins are reviewed for safe deserialization practices."

Missing Implementation:

• Example:
  • "The legacy_data column uses a custom Sequel plugin for YAML deserialization, and the plugin's safety is not verified."
  • "There is no comprehensive validation of data deserialized by Sequel plugins in all parts of the application."