mitigations.md

Mitigation Strategies Analysis for realm/realm-java

Mitigation Strategy: Implement Realm Encryption

Description:

• Step 1: Generate a strong encryption key. This key should be at least 64 bytes (512 bits) long and generated using a cryptographically secure random number generator.
• Step 2: Securely store the encryption key. Utilize Android Keystore or similar platform-specific secure storage mechanisms.
  • For Android Keystore: Generate or import the key into the Keystore. Access the key using its alias when opening the Realm.
  • Avoid storing the key in SharedPreferences, application code, or external files.
• Step 3: When configuring your Realm, provide the encryption key using RealmConfiguration.Builder.encryptionKey().
• Step 4: Ensure all Realm instances are opened using the same encryption key. Inconsistent key usage will lead to errors and data access issues.
• Step 5: Test encryption by attempting to access the Realm database file outside of the application (e.g., using a file explorer). Verify that the data is unreadable without the encryption key.

List of Threats Mitigated:

• Data Breach due to Device Compromise - Severity: High
  • Threat: If a device is lost, stolen, or infected with malware, unauthorized individuals or malicious software could access the unencrypted Realm database file and read sensitive data.
• Data Leakage through Backup or Debugging - Severity: Medium
  • Threat: Unencrypted Realm databases included in device backups or accessed during debugging sessions could expose sensitive data if these backups or debugging environments are not properly secured.

Impact:

• Data Breach due to Device Compromise: Significantly reduces risk. Encryption renders the database file unreadable without the key, making data access extremely difficult for unauthorized parties.
• Data Leakage through Backup or Debugging: Moderately reduces risk. Encryption protects the data within the database file itself, but security of backups and debugging environments still needs to be considered separately.

Currently Implemented:

• Encryption is implemented for the main user data Realm file (user_data.realm).
• Encryption key is generated upon first application launch and stored in Android Keystore using a unique alias.
• RealmConfiguration for user_data.realm is set with the encryption key.

Missing Implementation:

• Encryption is not yet implemented for the Realm file used for caching temporary data (cache_data.realm).
• Key rotation strategy is not implemented. The encryption key remains the same throughout the application lifecycle.

Mitigation Strategy: Secure Key Management

Description:

• Step 1: Utilize Android Keystore (or equivalent): Always store the Realm encryption key in a secure hardware-backed keystore like Android Keystore on Android devices. This prevents the key from being easily extracted from the application's process memory or file system.
• Step 2: Avoid Hardcoding: Never hardcode the encryption key directly in the application's source code. This makes the key easily discoverable through reverse engineering.
• Step 3: Restrict Key Access: Ensure that only the application process has access to the encryption key stored in the Keystore. Configure Keystore permissions appropriately.
• Step 4: Consider Key Rotation (Advanced): Implement a key rotation strategy to periodically change the encryption key. This limits the window of opportunity if a key is ever compromised. Key rotation requires careful planning and migration of encrypted data.
• Step 5: Regular Security Audits: Periodically review the key management implementation to ensure it adheres to best practices and remains secure against evolving threats.

List of Threats Mitigated:

• Encryption Key Compromise - Severity: High
  • Threat: If the encryption key is compromised, the entire Realm database can be decrypted, negating the benefits of encryption. This can happen if the key is stored insecurely or is easily guessable.
• Reverse Engineering Attacks - Severity: Medium
  • Threat: If the encryption key is embedded in the application code, attackers can reverse engineer the application to extract the key and decrypt the Realm database.

Impact:

• Encryption Key Compromise: Significantly reduces risk. Secure key storage in Keystore makes key extraction extremely difficult, even if the application is compromised.
• Reverse Engineering Attacks: Significantly reduces risk. Storing the key outside of the application code in a secure keystore prevents easy extraction through reverse engineering.

Currently Implemented:

• Encryption key is stored in Android Keystore.
• Key is accessed programmatically using its alias and the Keystore API.
• Hardcoding of the key is avoided.

Missing Implementation:

• Key rotation strategy is not implemented.
• Formal security audit of key management practices has not been conducted recently.

Mitigation Strategy: Implement Schema Migrations Carefully

Description:

• Step 1: Version Control: Use Realm's schemaVersion in RealmConfiguration to track schema changes. Increment the schemaVersion whenever you modify your Realm object models (classes).
• Step 2: Migration Block: Provide a migration block in RealmConfiguration.Builder. This block will be executed when the application detects a schema version mismatch between the application code and the existing Realm database file.
• Step 3: Step-by-Step Migrations: Within the migration block, write code to handle schema changes incrementally.
  • Use oldVersion and newVersion parameters in the migration block to determine the migration path.
  • Use DynamicRealm to access and modify the schema and data during migration.
  • Rename fields, add new fields, remove fields, and transform data as needed.
• Step 4: Data Validation: After each migration step, validate the data to ensure it is consistent and correct. Handle potential data conversion errors gracefully.
• Step 5: Testing: Thoroughly test schema migrations in development and staging environments with various schema versions and data sets before deploying to production. Include edge cases and error scenarios in your testing.
• Step 6: Rollback Strategy (Advanced): Consider implementing a rollback strategy in case a migration fails in production. This might involve backing up the Realm database before migration or having a mechanism to revert to a previous schema version.

List of Threats Mitigated:

• Data Corruption due to Schema Mismatch - Severity: High
  • Threat: If schema migrations are not handled correctly, the application might attempt to access data using an outdated schema, leading to data corruption, application crashes, or unexpected behavior.
• Data Loss during Schema Updates - Severity: Medium
  • Threat: Incorrect migration logic could result in data loss during schema updates, especially when renaming or removing fields or transforming data.
• Application Instability during Schema Updates - Severity: Medium
  • Threat: Poorly implemented migrations can cause application crashes or instability during the migration process, leading to a negative user experience.

Impact:

• Data Corruption due to Schema Mismatch: Significantly reduces risk. Proper schema migrations ensure data consistency and prevent application errors caused by schema mismatches.
• Data Loss during Schema Updates: Moderately reduces risk. Careful migration logic and data validation minimize the risk of data loss during schema updates.
• Application Instability during Schema Updates: Moderately reduces risk. Thorough testing and robust migration logic reduce the likelihood of application crashes during schema updates.

Currently Implemented:

• schemaVersion is used and incremented for each schema change.
• A migration block is defined in RealmConfiguration.
• Basic field renaming and addition migrations are implemented.
• Testing is performed in development environments.

Missing Implementation:

• Complex data transformations within migrations are not fully implemented and tested.
• Data validation after migrations is not consistently performed.
• Rollback strategy for failed migrations is not implemented.
• Testing in staging environments is not consistently performed for schema migrations.

Mitigation Strategy: Utilize Transactions Properly

Description:

• Step 1: Always Use Transactions: Enclose all Realm write operations (create, update, delete) within transactions. Use Realm.executeTransaction() for synchronous operations or Realm.executeTransactionAsync() for asynchronous operations.
• Step 2: Keep Transactions Short: Minimize the duration of transactions. Perform only the necessary write operations within a single transaction. Long-running transactions can lead to performance issues and increased contention.
• Step 3: Avoid Nested Transactions (Generally): While Realm supports nested transactions, they can increase complexity and potential for errors. Generally, aim for flat, well-defined transactions.
• Step 4: Handle Transaction Errors: Implement error handling within transaction blocks. If a transaction fails (e.g., due to exceptions), ensure that the application handles the error gracefully and potentially retries the operation or informs the user.
• Step 5: Thread Safety: Be mindful of thread safety when using Realm transactions, especially in multi-threaded applications. Ensure that Realm instances are properly managed and accessed within the correct threads.

List of Threats Mitigated:

• Data Inconsistency due to Concurrent Modifications - Severity: Medium
  • Threat: Without transactions, concurrent write operations from different threads or processes could lead to data inconsistencies and race conditions, resulting in corrupted or incorrect data.
• Data Corruption due to Partial Writes - Severity: Medium
  • Threat: If write operations are not atomic (within transactions), a partial write operation interrupted by an error or application crash could leave the database in an inconsistent state.

Impact:

• Data Inconsistency due to Concurrent Modifications: Moderately reduces risk. Transactions ensure atomicity and isolation of write operations, preventing race conditions and data inconsistencies in concurrent environments.
• Data Corruption due to Partial Writes: Moderately reduces risk. Transactions ensure that write operations are all-or-nothing. If a transaction fails, changes are rolled back, preventing partial writes and data corruption.

Currently Implemented:

• Realm.executeTransaction() is used for most synchronous write operations.
• Realm.executeTransactionAsync() is used for asynchronous write operations in background tasks.
• Basic error handling is implemented within transaction blocks (logging exceptions).

Missing Implementation:

• Transaction durations are not actively monitored or optimized to ensure they remain short.
• Nested transactions are occasionally used, increasing complexity.
• More robust error handling and retry mechanisms for transaction failures are not implemented.
• Thread safety considerations for Realm transactions are not formally documented or reviewed.

Mitigation Strategy: Validate Data on Write

Description:

• Step 1: Define Validation Rules: Establish clear validation rules for all data being written to Realm. These rules should cover data types, ranges, formats, required fields, and business logic constraints.
• Step 2: Implement Validation Logic: Implement validation logic in your application code before writing data to Realm. This can be done in data models, service layers, or input handling components.
• Step 3: Use Realm Constraints (Basic): Utilize Realm's built-in constraints like @Required, @Index, and data type restrictions in your Realm object models to enforce basic data integrity at the schema level.
• Step 4: Error Handling: If validation fails, prevent the data from being written to Realm. Provide informative error messages to the user or log validation errors for debugging and monitoring.
• Step 5: Server-Side Validation (If Applicable): If your application interacts with a backend server, consider implementing server-side validation as well to provide an additional layer of defense and ensure data consistency across the system.

List of Threats Mitigated:

• Data Integrity Issues due to Invalid Data - Severity: Medium
  • Threat: Storing invalid or inconsistent data in Realm can lead to application errors, unexpected behavior, and potentially security vulnerabilities if this invalid data is later processed without proper validation.
• Application Logic Errors due to Bad Data - Severity: Medium
  • Threat: Invalid data in Realm can cause application logic to malfunction, leading to incorrect calculations, display errors, or other functional issues.
• Potential Security Vulnerabilities from Unvalidated Input - Severity: Low to Medium (depending on context)
  • Threat: In some cases, storing unvalidated input directly into Realm could potentially open up avenues for injection attacks or other security vulnerabilities if this data is later used in sensitive operations without proper sanitization.

Impact:

• Data Integrity Issues due to Invalid Data: Moderately reduces risk. Data validation ensures that only valid and consistent data is stored in Realm, improving data quality and application reliability.
• Application Logic Errors due to Bad Data: Moderately reduces risk. Validating data prevents application logic from operating on incorrect or unexpected data, reducing the likelihood of functional errors.
• Potential Security Vulnerabilities from Unvalidated Input: Minimally to Moderately reduces risk. Data validation can help prevent some types of input-related vulnerabilities, but comprehensive security measures are still required.

Currently Implemented:

• Basic data type constraints are used in Realm object models (e.g., using String, int, Date types).
• @Required annotation is used for some mandatory fields.
• Limited application-level validation is implemented for certain data inputs.

Missing Implementation:

• Comprehensive validation rules are not formally defined for all data models.
• Application-level validation logic is not consistently applied across all data write operations.
• Server-side validation is not implemented (application currently does not have a backend server component).
• Error handling for validation failures is not consistently implemented and user-friendly error messages are not always provided.