threat-modeling.md

Threat Model Analysis for yiisoft/yii2

Threat: Component Misconfiguration - Database Credentials Exposure (via db Component)

• Description: An attacker gains access to database credentials due to misconfiguration of the Yii2 db component. This specifically involves scenarios where Yii2's configuration mechanisms are misused, such as leaving YII_DEBUG enabled in production, which can cause Yii2's error handling to expose database connection details. The attacker exploits Yii2's debug features or error messages that are improperly displayed due to the framework's configuration.
• Impact: Complete database compromise. The attacker can read, modify, or delete all data. This leads to data breaches, data loss, and application downtime.
• Affected Yii2 Component: yii\db\Connection (the db application component), yii\base\ErrorHandler (when misconfigured in debug mode).
• Risk Severity: Critical
• Mitigation Strategies:
  • Disable debug mode in production (YII_DEBUG set to false in the index.php and any console entry scripts).
  • Store database credentials securely outside of the Yii2 configuration files, using environment variables or a secure configuration management system.
  • Configure Yii2's error handler (errorHandler component) to display generic error messages in production, not detailed stack traces or configuration details.

Threat: Gii Exploitation in Production (Direct Yii2 Module)

• Description: An attacker discovers that the Yii2 Gii module (yii\gii\Module) is enabled and accessible in a production environment. The attacker directly interacts with the Gii module's web interface to generate malicious code or access sensitive information about the application's structure. This is a direct exploitation of a Yii2-provided feature.
• Impact: Remote code execution, information disclosure, complete application compromise. The attacker could gain full control of the application and server.
• Affected Yii2 Component: yii\gii\Module (the Gii module).
• Risk Severity: Critical
• Mitigation Strategies:
  • Completely disable the Gii module in production environments. Remove the gii module configuration from the production configuration file (config/web.php or similar). Ensure it's not loaded by any entry script.

Threat: Debug Toolbar Data Leakage (Direct Yii2 Module)

• Description: The Yii2 debug toolbar module (yii\debug\Module) is enabled in production. An attacker accesses the application and directly views the debug toolbar, which exposes sensitive information like database queries, session data, and request parameters. This is a direct exploitation of a Yii2-provided feature being misconfigured.
• Impact: Information disclosure. The attacker gains insights into the application's inner workings, potentially aiding further attacks. Exposure of sensitive data (API keys, user credentials) could lead to direct compromise.
• Affected Yii2 Component: yii\debug\Module (the debug module).
• Risk Severity: High
• Mitigation Strategies:
  • Disable the debug toolbar module in production environments. Remove the debug module configuration from the production configuration file.

Threat: Session Fixation via Misconfigured user Component (Yii2 Session Handling)

• Description: An attacker sets a user's session ID before authentication. Due to misconfiguration of Yii2's yii\web\User component (specifically, failing to regenerate the session ID after login), the attacker hijacks the user's session. This exploits a flaw in how Yii2's session management is used, not a vulnerability in the session handling itself if used correctly.
• Impact: Session hijacking. The attacker impersonates the authenticated user.
• Affected Yii2 Component: yii\web\User (the user application component), yii\web\Session.
• Risk Severity: High
• Mitigation Strategies:
  • Ensure that Yii2's session ID regeneration after authentication is not disabled. Verify that yii\web\User::$enableAutoLogin and related settings are configured securely and that the default behavior of regenerating the session ID on login is maintained. Explicitly call $session->regenerateID() after successful login if there's any doubt.

Threat: Unsafe Deserialization from Cache (Yii2 Cache Component)

• Description: An attacker compromises the cache backend used by Yii2's yii\caching\Cache component (e.g., a shared file system, a vulnerable Redis server). The attacker injects a malicious serialized object. When Yii2's Cache component deserializes this object, it triggers arbitrary PHP code execution. This is a direct attack on Yii2's caching mechanism.
• Impact: Remote code execution. The attacker can execute arbitrary PHP code.
• Affected Yii2 Component: yii\caching\Cache and its implementations (e.g., yii\caching\FileCache, yii\caching\MemCache, yii\caching\RedisCache).
• Risk Severity: High
• Mitigation Strategies:
  • Use a secure cache backend, properly configured. For FileCache, ensure the cache directory is not web-accessible and has strict permissions. For shared cache servers (Memcached, Redis), use strong authentication and network restrictions.
  • Avoid storing objects that rely on complex deserialization logic in the Yii2 cache.
  • If deserialization of potentially untrusted data is absolutely necessary within the context of Yii2's caching, use a safe deserialization library or implement strict validation of the serialized data before Yii2's unserialize() is called. This is a very advanced mitigation and should be avoided if possible.
  • Use a different serialization format, like JSON, if possible, for data stored in the Yii2 cache.

Threat: RBAC Misconfiguration - Privilege Escalation (Yii2 RBAC Component)

• Description: The Yii2 RBAC system (yii\rbac\ManagerInterface and implementations) is misconfigured, granting users or roles excessive permissions. An attacker exploits this misconfiguration of the Yii2 RBAC component to perform unauthorized actions. This is a direct vulnerability arising from improper use of Yii2's built-in authorization system.
• Impact: Privilege escalation, unauthorized data access/modification, potential application compromise.
• Affected Yii2 Component: yii\rbac\ManagerInterface and its implementations (e.g., yii\rbac\PhpManager, yii\rbac\DbManager).
• Risk Severity: High
• Mitigation Strategies:
  • Carefully design and implement RBAC rules, following the principle of least privilege. Use Yii2's RBAC API correctly.
  • Regularly audit RBAC configurations within Yii2 to ensure correctness.
  • Use a hierarchical RBAC structure within Yii2 to simplify management.
  • Thoroughly test RBAC rules implemented using Yii2's components.
  • Avoid using default Yii2 RBAC roles and permissions without customization.