attack-surface.md

Attack Surface Analysis for php-fig/container

Attack Surface: 1. Insecure Container Configuration Storage

• Description: Container configuration files, which define application dependencies and parameters, are stored in publicly accessible locations, exposing sensitive application internals.
• Container Contribution: The container relies on these configuration files to function. Exposing them directly reveals the application's dependency graph and potential configuration secrets managed by the container.
• Example: Container configuration files (e.g., services.yaml, config.php) are placed within the web root. Attackers can directly access these files via HTTP requests, revealing database credentials or API keys defined as container parameters.
• Impact: Information disclosure of sensitive configuration data, enabling deeper understanding of application architecture for targeted attacks, potential direct access to backend systems using revealed credentials.
• Risk Severity: High
• Mitigation Strategies:
  • Store configuration files outside the web root: Ensure configuration files are located in directories inaccessible via direct web requests.
  • Utilize environment variables or secure vaults for sensitive parameters: Avoid hardcoding secrets in configuration files. Leverage environment variables or dedicated secret management systems that the container can access.
  • Implement strict file access controls: Restrict read access to configuration files to only the application user and necessary processes.

Attack Surface: 2. Misconfigured Dependency Definitions

• Description: Incorrect or overly permissive dependency definitions within the container configuration lead to unintended object instantiation, service injection, or exposure of internal components.
• Container Contribution: The container's core function is dependency resolution and injection based on configuration. Misconfigurations in these definitions directly translate to vulnerabilities in the application's dependency wiring.
• Example: A service definition mistakenly allows injecting an administrative service into a user-facing controller due to an incorrect class name or scope definition. A regular user can then access administrative functionalities through the compromised controller.
• Impact: Privilege escalation, unauthorized access to functionalities, potential for data manipulation or corruption due to unintended service interactions, application logic bypass.
• Risk Severity: High to Critical (depending on the severity of the misconfiguration and exposed functionality)
• Mitigation Strategies:
  • Rigorous review and testing of container configurations: Implement thorough code reviews specifically focused on container definitions and dependency wiring.
  • Static analysis and linting for configuration: Utilize tools that can automatically validate container configurations against security best practices and detect potential misconfigurations.
  • Comprehensive unit and integration testing of dependency injection: Create tests that specifically verify the correct wiring of dependencies and ensure services are injected as intended, preventing unintended exposures.
  • Principle of least privilege in service definitions: Define service scopes and access levels to minimize the potential impact of misconfigurations.

Attack Surface: 3. External Configuration Sources Vulnerabilities

• Description: The container relies on external, potentially insecure sources (environment variables, databases, remote configuration servers) for configuration, making these sources attack vectors.
• Container Contribution: Containers often offer flexibility by supporting configuration loading from diverse external sources. If these sources are compromised, the container becomes a conduit for injecting malicious configurations.
• Example: The container reads service definitions from a database. An attacker gains SQL injection vulnerability in the application's database access layer and manipulates the database records containing container configurations, injecting malicious service definitions that execute arbitrary code upon container initialization.
• Impact: Remote code execution, complete application takeover, data breaches, denial of service through manipulated service behavior.
• Risk Severity: Critical
• Mitigation Strategies:
  • Secure and harden external configuration sources: Implement robust security measures for all external sources used for container configuration (e.g., strong authentication, access controls, network segmentation).
  • Input validation and sanitization for external configuration data: Treat data retrieved from external sources as untrusted input and rigorously validate and sanitize it before using it in container definitions.
  • Minimize reliance on external sources for critical security configurations: Avoid storing sensitive security-related configurations in external sources if possible.
  • Implement monitoring and integrity checks for external configuration sources: Monitor for unauthorized changes and implement mechanisms to verify the integrity of configuration data loaded from external sources.

Attack Surface: 4. Deserialization Vulnerabilities in Configuration Handling

• Description: If the container implementation utilizes insecure deserialization for configuration caching or loading, attackers can exploit this to achieve remote code execution by providing malicious serialized data.
• Container Contribution: Some container implementations might employ serialization for performance optimizations like configuration caching. If this deserialization process is vulnerable, it becomes a direct and critical attack vector through the container itself.
• Example: A container implementation caches compiled configuration in serialized PHP objects. An attacker identifies a deserialization vulnerability in the container's cache loading mechanism and injects a crafted serialized payload into the cache storage. Upon the container loading the cache, the malicious payload is deserialized, leading to remote code execution.
• Impact: Remote code execution, complete server compromise, full control over the application and underlying infrastructure.
• Risk Severity: Critical
• Mitigation Strategies:
  • Avoid deserialization for configuration caching or loading if possible: Explore alternative caching mechanisms that do not involve deserialization, such as opcode caching or simple file-based caching of processed configuration.
  • If deserialization is unavoidable, use secure deserialization practices: Employ secure deserialization libraries and techniques that mitigate common deserialization vulnerabilities.
  • Implement integrity checks and signatures for serialized configuration data: Digitally sign or use HMAC to verify the integrity of serialized configuration data, preventing tampering and injection of malicious payloads.
  • Regularly update the container library and PHP version: Ensure the container implementation and underlying PHP environment are patched against known deserialization vulnerabilities.

Attack Surface: 5. Factory Function/Callable Vulnerabilities (Unsafe Logic or Input Handling)

• Description: Factory functions or callables used to define and create services within the container configuration contain insecure logic or improperly handle external or user-controlled inputs.
• Container Contribution: Containers provide flexibility through factory functions, allowing complex service creation logic. However, vulnerabilities within these factories become part of the containerized application's attack surface.
• Example: A factory function responsible for creating a database connection object directly uses user-provided input (e.g., from request parameters) to construct the connection string without proper sanitization. This allows an attacker to inject malicious parameters into the connection string, potentially leading to database compromise or unauthorized data access.
• Impact: Data breaches, unauthorized access to backend systems, potential for code execution within the factory function's context, application logic bypass.
• Risk Severity: High to Critical (depending on the vulnerability in the factory function and the resources it interacts with)
• Mitigation Strategies:
  • Thoroughly sanitize and validate all inputs to factory functions: Treat all external or user-controlled inputs used within factory functions as untrusted and apply rigorous input validation and sanitization techniques.
  • Minimize the use of user-controlled input in factory functions: Design factories to rely on pre-validated or securely managed configuration rather than directly processing user input.
  • Apply the principle of least privilege to factory functions: Limit the access and permissions of factory functions to only the resources strictly necessary for their operation.
  • Regularly audit and security review factory function code: Conduct code reviews and security audits specifically targeting factory functions to identify potential vulnerabilities in their logic and input handling.

Attack Surface: 6. Bugs and Vulnerabilities in Chosen Container Implementation

• Description: The specific container implementation library chosen (e.g., PHP-DI, Symfony DI) contains inherent software bugs or security vulnerabilities within its codebase.
• Container Contribution: The php-fig/container interface is a specification. The actual security posture is determined by the chosen implementation. Vulnerabilities in the implementation directly impact all applications using it.
• Example: A specific version of a popular container library has a discovered vulnerability that allows for remote code execution through a crafted service definition or during dependency resolution. Applications using this vulnerable version are directly exposed to this critical risk.
• Impact: Varies depending on the vulnerability - can range from denial of service and information disclosure to remote code execution and complete application compromise.
• Risk Severity: Varies - can be High to Critical depending on the specific vulnerability.
• Mitigation Strategies:
  • Choose a reputable and actively maintained container implementation: Select a container library that is well-established, actively developed, and has a strong security track record.
  • Stay updated with security advisories and patch releases: Regularly monitor security advisories and promptly apply security patches and updates released by the container library maintainers.
  • Implement dependency scanning and vulnerability management: Utilize automated tools to scan application dependencies, including the container library, for known vulnerabilities and manage remediation efforts.
  • Participate in security communities and report vulnerabilities: Engage with security communities and report any discovered vulnerabilities in container implementations to contribute to the overall security of the ecosystem.