attack-tree.md

Attack Tree Analysis for yiisoft/yii2

Objective: Compromise Yii2 Application by Exploiting Yii2 Weaknesses

Attack Tree Visualization

• Compromise Yii2 Application [CRITICAL NODE]
  • Exploit Yii2 Framework Vulnerabilities [HIGH RISK PATH]
    • Remote Code Execution (RCE) [CRITICAL NODE] [HIGH RISK PATH]
      • Unserialize Vulnerabilities [HIGH RISK PATH]
        • Exploit vulnerable unserialize calls in Yii2 core (e.g., session handling, caching if misconfigured). [HIGH RISK PATH]
        • Exploit vulnerable unserialize calls in Yii2 extensions. [HIGH RISK PATH]
      • Template Injection (Twig/PHP) [HIGH RISK PATH]
        • Exploit vulnerabilities in user-provided input being directly used in template rendering. [HIGH RISK PATH]
    • Database Exploitation via Framework Features [HIGH RISK PATH]
      • SQL Injection through insecure use of Active Record or Query Builder. [CRITICAL NODE]
  • Exploit Yii2 Configuration Weaknesses [HIGH RISK PATH]
    • Debug Mode Enabled in Production [CRITICAL NODE] [HIGH RISK PATH]
      • Information Disclosure [HIGH RISK PATH]
      • Code Execution via Debug Toolbar (if accessible and vulnerable). [HIGH RISK PATH]
    • Weak or Default Security Keys/Cookies [CRITICAL NODE] [HIGH RISK PATH]
      • Predictable or default cookie validation keys (cookieValidationKey in config). [HIGH RISK PATH]
  • Exploit Yii2 Extension Vulnerabilities [HIGH RISK PATH]
    • Vulnerable Yii2 Extensions [HIGH RISK PATH]
      • Using outdated or unmaintained extensions with known vulnerabilities. [HIGH RISK PATH]

Attack Tree Path: Remote Code Execution (RCE)

Attack Vector: Achieving arbitrary code execution on the server, allowing the attacker to fully compromise the application and potentially the underlying system.

• Breakdown:
  • **Unserialize Vulnerabilities [HIGH RISK PATH]:
    • Exploit vulnerable unserialize calls in Yii2 core:
      • How: Yii2, like PHP itself, uses unserialize() for session handling, caching, and potentially other internal mechanisms. If vulnerable classes are present in the application (or its dependencies, including Yii2 core itself if outdated), an attacker can craft a malicious serialized payload. When this payload is unserialized by the application, it can trigger arbitrary code execution.
      • Example: Exploiting known vulnerabilities in PHP's unserialize() function in conjunction with classes present in Yii2 or its dependencies (e.g., gadget chains).
    • Exploit vulnerable unserialize calls in Yii2 extensions:
      • How: Yii2 extensions might also use unserialize() in their code. If these extensions handle user-controlled data that gets unserialized, and if vulnerable classes are present, RCE can be achieved.
      • Example: An extension that caches data using serialization and doesn't properly sanitize input before unserializing it.
  • **Template Injection (Twig/PHP) [HIGH RISK PATH]:
    • Exploit vulnerabilities in user-provided input being directly used in template rendering:
      • How: While Yii2 encourages secure template practices, developers might mistakenly use user-provided input directly within template code without proper escaping or sanitization. If Twig or PHP template engine is used in a way that allows execution of arbitrary code based on user input, template injection vulnerabilities arise.
      • Example: A developer might dynamically construct a template path based on user input, or directly embed user input within a Twig {{ ... }} block without proper filtering, leading to code execution within the template rendering context.

Attack Tree Path: SQL Injection through insecure use of Active Record or Query Builder

Attack Vector: Injecting malicious SQL code into database queries, allowing the attacker to read, modify, or delete data, bypass authentication, or potentially execute operating system commands on the database server (depending on database configuration).

• Breakdown:
  • How: Developers might bypass Yii2's secure query building mechanisms by:
    • Using raw SQL queries (Yii::$app->db->createCommand($rawSql)) without proper parameterization.
    • Insecurely concatenating user input directly into query builder methods or conditions.
    • Misusing Active Record features in a way that allows injection.
  • Example: Constructing a WHERE clause in Active Record using string concatenation with unsanitized user input, instead of using parameterized conditions.

Attack Tree Path: Debug Mode Enabled in Production

Attack Vector: Exposing sensitive information and potentially enabling code execution due to debug mode being active in a live, production environment.

• Breakdown:
  • **Information Disclosure [HIGH RISK PATH]:
    • How: When debug mode is enabled, Yii2 displays verbose error pages, application configuration details, database credentials, internal paths, and potentially even source code snippets in case of errors. This information can be invaluable to an attacker for reconnaissance and further exploitation.
    • Example: An attacker encountering an error in the application in production sees a detailed stack trace revealing file paths, database connection strings, and potentially sensitive configuration parameters.
  • **Code Execution via Debug Toolbar (if accessible and vulnerable) [HIGH RISK PATH]:
    • How: The Yii2 debug toolbar, when enabled and accessible in production (which it should never be), might contain vulnerabilities itself or provide functionalities that can be abused for code execution if not properly secured.
    • Example: If the debug toolbar allows execution of arbitrary PHP code snippets or provides access to internal application components that can be manipulated to execute code.

Attack Tree Path: Weak or Default Security Keys/Cookies

Attack Vector: Compromising application security by using weak, predictable, or default values for security-sensitive configurations, particularly the cookieValidationKey.

• Breakdown:
  • **Predictable or default cookie validation keys (cookieValidationKey in config) [HIGH RISK PATH]:
    • How: The cookieValidationKey is crucial for signing and validating cookies, including session cookies. If this key is weak, default, or easily guessable (or leaked), an attacker can forge valid cookies, including session cookies, to impersonate users or bypass authentication.
    • Example: An application using the default cookieValidationKey from an old Yii2 version or a key that is easily cracked through brute-force or rainbow table attacks.

Attack Tree Path: Vulnerable Yii2 Extensions

Attack Vector: Exploiting vulnerabilities present in third-party Yii2 extensions used by the application.

• Breakdown:
  • **Using outdated or unmaintained extensions with known vulnerabilities [HIGH RISK PATH]:
    • How: Yii2 applications often rely on extensions for added functionality. If these extensions are outdated, unmaintained, or poorly coded, they might contain known vulnerabilities (SQL injection, XSS, RCE, etc.). Attackers can target these known vulnerabilities to compromise the application.
    • Example: Using an old version of a popular Yii2 extension that has a publicly disclosed SQL injection vulnerability.

Attack Tree Path: Exploit Yii2 Framework Vulnerabilities

Attack Tree Path: Unserialize Vulnerabilities

Attack Tree Path: Exploit vulnerable unserialize calls in Yii2 core

Attack Tree Path: Exploit vulnerable unserialize calls in Yii2 extensions

Attack Tree Path: Template Injection (Twig/PHP)

Attack Tree Path: Exploit vulnerabilities in user-provided input being directly used in template rendering

Attack Tree Path: Database Exploitation via Framework Features

Attack Tree Path: Exploit Yii2 Configuration Weaknesses

Attack Tree Path: Information Disclosure

Attack Tree Path: Code Execution via Debug Toolbar (if accessible and vulnerable)

Attack Tree Path: Predictable or default cookie validation keys (cookieValidationKey in config)

Attack Tree Path: Exploit Yii2 Extension Vulnerabilities

Attack Tree Path: Using outdated or unmaintained extensions with known vulnerabilities