mitigations.md

Mitigation Strategies Analysis for dart-lang/json_serializable

Mitigation Strategy: 1. Input Validation After Deserialization

• Mitigation Strategy: Input Validation After Deserialization (json_serializable Context)
• Description:
  1. Identify json_serializable Deserialization Points: Locate all instances in your project where you are using fromJson methods generated by json_serializable to convert JSON data into Dart objects. These are the entry points for external data into your application via json_serializable.
  2. Define Validation Rules for Deserialized Objects: For each Dart class deserialized using json_serializable, specify validation rules that must be enforced after the JSON structure is processed by json_serializable. These rules should focus on the content of the deserialized fields, as json_serializable primarily handles structure.
     • Example Rules: For a User class with an email field, a rule might be "email must be a valid email format". For an age field, a rule might be "age must be a positive integer between 0 and 120".
  3. Implement Validation Logic Post fromJson: Immediately after calling the fromJson method generated by json_serializable, invoke your validation logic. This can be implemented as:
     • Validation Methods within Model Classes: Add validation methods directly to your @JsonSerializable classes that are called after deserialization.
     • Dedicated Validator Classes/Functions: Create separate validator functions or classes that take the deserialized object as input and perform validation checks.
  4. Handle Validation Failures: Implement error handling to manage cases where validation fails. This should include:
     • Rejecting Invalid Data: Prevent the application from processing data that fails validation.
     • Logging Errors: Log validation failures for debugging and security monitoring purposes.
     • Returning Errors to the Source (If Applicable): If the JSON data originates from an external source (e.g., API request), return appropriate error responses indicating validation failures.
• List of Threats Mitigated:
  • Data Integrity Violation (High Severity): json_serializable itself does not validate data content. Malicious or malformed JSON, even if structurally correct for json_serializable, can introduce invalid or harmful data into your application, leading to data corruption or unexpected behavior.
  • Injection Attacks (Medium to High Severity): If json_serializable deserializes string data from untrusted sources that is later used in contexts susceptible to injection (e.g., web rendering, database queries), and validation is missing, it can enable injection attacks.
  • Business Logic Errors (Medium Severity): Invalid data deserialized by json_serializable can violate business rules and cause application logic to malfunction, leading to incorrect outputs or application errors.
• Impact:
  • Data Integrity Violation (High Impact): Directly addresses the risk of invalid data entering the application through json_serializable deserialization, ensuring data processed is valid according to application rules.
  • Injection Attacks (High Impact): Mitigates injection risks by validating and sanitizing data after it has been processed by json_serializable but before it is used in potentially vulnerable contexts.
  • Business Logic Errors (High Impact): Prevents application errors and unexpected behavior caused by invalid data that json_serializable might otherwise pass through without content validation.
• Currently Implemented: Basic type enforcement by Dart during deserialization might be implicitly present. Some ad-hoc validation might exist in specific parts of the application, but likely not consistently applied after json_serializable deserialization.
• Missing Implementation: Systematic and comprehensive input validation specifically after using json_serializable's fromJson methods is likely missing across the project. Formalized validation rules tied to json_serializable models are probably not defined or consistently enforced.

Mitigation Strategy: 2. Secure Handling of Sensitive Data during Serialization and Deserialization with json_serializable

• Mitigation Strategy: Secure Sensitive Data Handling (json_serializable Context)
• Description:
  1. Identify Sensitive Fields in @JsonSerializable Classes: Review your Dart classes annotated with @JsonSerializable and explicitly identify fields that contain sensitive data (e.g., passwords, API keys, PII).
  2. Control Serialization with @JsonKey and Custom Logic: Utilize @JsonKey annotations and custom toJson/fromJson logic within your @JsonSerializable classes to manage how sensitive data is handled during serialization and deserialization:
     • @JsonKey(ignore: true) for Exclusion: If a sensitive field should never be serialized into JSON by json_serializable, annotate it with @JsonKey(ignore: true). This prevents json_serializable from including it in the JSON output.
     • Custom toJson for Redaction/Omission: For more complex scenarios, implement a custom toJson method in your @JsonSerializable class. Within this method, you can conditionally omit sensitive fields or redact them (e.g., replace with placeholder values) before returning the JSON representation.
     • Custom fromJson for Secure Deserialization/Decryption: If sensitive data is serialized in an encrypted form (outside of json_serializable's direct handling), use a custom fromJson method to handle decryption after json_serializable has processed the basic JSON structure.
  3. Encryption Before Serialization (External to json_serializable, but relevant): If sensitive data must be serialized, encrypt it before it is processed by json_serializable. Store the encrypted data in the fields that json_serializable will serialize. Decrypt after deserialization using custom fromJson logic as mentioned above. This keeps json_serializable handling the structure, while encryption is managed separately.
  4. Avoid Logging Serialized Sensitive Data: When logging or debugging, be extremely cautious about logging the JSON output generated by json_serializable if it might contain sensitive data. Implement logging practices that prevent sensitive data from being exposed in logs.
• List of Threats Mitigated:
  • Data Exposure via Serialization (High Severity): json_serializable by default will serialize all annotated fields. If sensitive data is not explicitly excluded or handled, it can be inadvertently included in JSON output, leading to exposure through network transmission, storage, or logs.
  • Data Breach via Logs (Medium to High Severity): If serialized JSON containing sensitive data is logged in plain text, it creates a vulnerability where attackers gaining access to logs can compromise sensitive information.
• Impact:
  • Data Exposure via Serialization (High Impact): Directly reduces the risk of sensitive data exposure by providing mechanisms within json_serializable's annotation and customization capabilities to control what data is serialized and how.
  • Data Breach via Logs (High Impact): Mitigates the risk of logging sensitive data by emphasizing the need to control serialization and avoid logging JSON outputs that might contain sensitive information processed by json_serializable.
• Currently Implemented: Developers might be generally aware of not logging passwords. Some sensitive fields might be manually excluded from serialization in specific, isolated cases.
• Missing Implementation: Systematic identification and secure handling of all sensitive data fields within @JsonSerializable classes are likely missing. Consistent use of @JsonKey(ignore: true) or custom toJson logic for sensitive data is probably not enforced. Encryption workflows integrated with json_serializable for sensitive data are likely absent.

Mitigation Strategy: 3. Code Review and Security Audits Focusing on json_serializable Usage

• Mitigation Strategy: Security-Focused Code Review & Audits (json_serializable Usage)
• Description:
  1. Prioritize json_serializable Code in Security Reviews: When conducting code reviews, specifically focus on code sections that utilize json_serializable for serialization and deserialization. Make this a dedicated area of scrutiny during reviews.
  2. Review Checklist for json_serializable Security: Develop a code review checklist that includes specific security considerations related to json_serializable usage:
     • Input Validation Post-Deserialization: Verify that proper input validation is implemented after using fromJson for all @JsonSerializable classes handling external data.
     • Sensitive Data Handling: Check for correct usage of @JsonKey(ignore: true), custom toJson, and custom fromJson for sensitive data fields in @JsonSerializable classes. Ensure sensitive data is not inadvertently serialized or logged.
     • Error Handling in Custom Logic: If custom toJson or fromJson methods are used, review them for proper error handling and secure coding practices.
     • Correct json_serializable Annotations: Verify that @JsonSerializable annotations and @JsonKey annotations are used correctly and securely, without misconfigurations that could lead to vulnerabilities.
  3. Security Audits Targeting json_serializable Integration: Include json_serializable usage as a specific focus area in periodic security audits.
     • Audit Scope: Ensure security audits explicitly cover the codebase related to json_serializable, including model classes, serialization/deserialization logic, and data validation processes around json_serializable.
     • Vulnerability Identification: Audits should aim to identify potential security weaknesses arising from incorrect or insecure usage of json_serializable, misconfigurations, or missing security controls in code interacting with json_serializable.
• List of Threats Mitigated:
  • Logic Errors in Serialization/Deserialization (Medium to High Severity): Subtle errors in how json_serializable is used, custom logic within @JsonSerializable classes, or misconfigurations of annotations can introduce vulnerabilities that are difficult to detect automatically.
  • Misconfiguration of json_serializable (Medium Severity): Incorrectly applied @JsonSerializable or @JsonKey annotations can lead to unintended security consequences, such as accidentally serializing sensitive data or bypassing intended security measures.
• Impact:
  • Logic Errors in Serialization/Deserialization (High Impact): Reduces the risk of logic errors by having human reviewers specifically examine the code related to json_serializable for potential flaws and security weaknesses.
  • Misconfiguration of json_serializable (Medium Impact): Helps identify and correct misconfigurations of json_serializable annotations and usage patterns that could lead to security vulnerabilities.
• Currently Implemented: Standard code reviews are likely performed, but might not specifically focus on json_serializable security aspects.
• Missing Implementation: Security-focused code reviews with checklists tailored to json_serializable usage are likely not consistently performed. Periodic security audits with a specific scope covering json_serializable integration are probably not conducted.