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attack-surface.md

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Attack Surface Analysis for apache/incubator-apisix

Attack Surface: Admin API Authentication Bypass

  • Description: Attackers bypass authentication mechanisms protecting the APISIX Admin API, gaining unauthorized administrative control over the gateway.
  • APISIX Contribution: APISIX provides the Admin API and its authentication mechanisms. Weak default settings or misconfigurations within APISIX directly expose this attack surface.
  • Example: Default APISIX Admin API key is used and publicly exposed. An attacker uses this key to access the Admin API and reconfigure routes to redirect traffic to a malicious server, leveraging APISIX's routing capabilities.
  • Impact: Full compromise of the APISIX API gateway, allowing attackers to control routing, plugins, and potentially backend services via APISIX. Data exfiltration, service disruption, and further attacks on backend systems are possible through APISIX.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Change Default Admin API Key: Immediately change the default admin_key in APISIX configuration to a strong, randomly generated secret.
    • Implement Strong Authentication: Utilize robust authentication methods supported by APISIX for the Admin API, such as mutual TLS (mTLS) or OAuth 2.0, if configured and applicable within APISIX.
    • Restrict Admin API Access: Limit network access to the Admin API at the network level, allowing only authorized networks or IP ranges to reach the APISIX Admin API port.
    • Regularly Rotate API Keys: Implement a policy for periodic rotation of Admin API keys used by APISIX.

Attack Surface: Admin API Injection Vulnerabilities

  • Description: Attackers inject malicious code or commands into the APISIX Admin API through input fields, exploiting vulnerabilities in input validation and sanitization within APISIX's Admin API handling.
  • APISIX Contribution: The APISIX Admin API design accepts user input for configuration. Insufficient input validation and sanitization in APISIX's Admin API code can lead to injection vulnerabilities.
  • Example: An attacker crafts a malicious payload within a route configuration (e.g., in a header value or upstream URL) that, when processed by the APISIX Admin API, results in command execution on the APISIX server due to a flaw in APISIX's input processing.
  • Impact: Remote code execution on the APISIX server, leading to full system compromise, data breach, and service disruption originating from a vulnerability in APISIX.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Strict Input Validation: Implement rigorous input validation and sanitization within APISIX Admin API code for all data received. Use whitelisting and parameterized queries where possible in APISIX's Admin API logic.
    • Principle of Least Privilege: Run APISIX processes with minimal necessary privileges at the OS level to limit the impact of successful code execution exploiting an APISIX vulnerability.
    • Regular Security Audits: Conduct regular security audits and penetration testing of the APISIX Admin API specifically focusing on input handling and injection points.
    • Keep APISIX Up-to-Date: Apply security patches and updates for APISIX and its dependencies promptly to address known vulnerabilities in APISIX code.

Attack Surface: Plugin Vulnerabilities (Core and Custom)

  • Description: Vulnerabilities exist within APISIX plugins, either core plugins shipped with APISIX or custom-developed plugins intended to extend APISIX functionality, allowing attackers to bypass security controls or cause other security issues within the APISIX gateway.
  • APISIX Contribution: APISIX's plugin architecture is a core feature. Bugs in plugins, whether developed by the APISIX project or by users, directly translate to vulnerabilities in the API gateway itself.
  • Example: A vulnerability in a core authentication plugin provided by APISIX allows attackers to bypass authentication checks and access protected backend services routed through APISIX. Or, a custom plugin developed in Lua for APISIX contains a buffer overflow vulnerability that can be exploited within the APISIX process.
  • Impact: Authentication bypass, authorization bypass, data leakage, denial of service, and potentially remote code execution depending on the plugin vulnerability within the APISIX context.
  • Risk Severity: High to Critical (depending on the vulnerability and plugin function)
  • Mitigation Strategies:
    • Security Reviews for Custom Plugins: Thoroughly review and security test all custom plugins developed for APISIX before deployment. Follow secure coding practices for Lua development in the context of APISIX plugins.
    • Use Official and Well-Maintained Plugins: Prefer using official, well-maintained core plugins provided by the APISIX project or plugins from trusted sources designed for APISIX.
    • Regularly Update Plugins: Keep all plugins, both core and custom used in APISIX, updated to the latest versions to patch known vulnerabilities in plugin code.
    • Plugin Sandboxing and Isolation: Explore and utilize any available plugin sandboxing or isolation mechanisms offered by APISIX to limit the impact of plugin vulnerabilities.
    • Disable Unnecessary Plugins: Disable any plugins within APISIX configuration that are not actively used to reduce the attack surface of the APISIX gateway.

Attack Surface: HTTP Request Smuggling

  • Description: Attackers manipulate HTTP requests in a way that causes APISIX and backend server to interpret request boundaries differently, leading to request smuggling and potential bypass of security controls implemented by APISIX or backend services.
  • APISIX Contribution: As an HTTP proxy, APISIX parses and forwards HTTP requests. Vulnerabilities in its HTTP parsing and handling logic within APISIX can lead to request smuggling issues, especially when interacting with diverse backend servers through APISIX.
  • Example: An attacker crafts a malicious HTTP/1.1 request with ambiguous Content-Length and Transfer-Encoding headers. APISIX due to a parsing flaw might forward the request, but the backend server interprets it differently, leading to a smuggled request being processed as a separate request, potentially bypassing authentication or authorization checks intended to be enforced by APISIX or the backend.
  • Impact: Authentication bypass, authorization bypass, access to unintended resources, cache poisoning, and potentially remote code execution on backend servers in certain scenarios due to request smuggling facilitated by APISIX.
  • Risk Severity: High
  • Mitigation Strategies:
    • Use HTTP/2 End-to-End: Where possible, use HTTP/2 for communication between clients, APISIX, and backend servers, as HTTP/2 is less susceptible to request smuggling vulnerabilities compared to HTTP/1.1 handled by APISIX.
    • Strict HTTP Parsing: Ensure APISIX and backend servers are configured with strict HTTP parsing and reject ambiguous or malformed requests at both APISIX and backend levels.
    • Normalize Requests: Implement request normalization within APISIX to ensure consistent interpretation of requests by both APISIX and backend servers when APISIX forwards requests.
    • Regular Security Testing: Conduct security testing specifically for HTTP request smuggling vulnerabilities targeting APISIX and its interaction with backends.

Attack Surface: Dependency Vulnerabilities (OpenResty/Nginx, Lua Libraries)

  • Description: Vulnerabilities in underlying dependencies used by APISIX, such as OpenResty/Nginx or Lua libraries, are exploited to compromise APISIX itself.
  • APISIX Contribution: APISIX relies on OpenResty and Lua libraries. Vulnerabilities in these dependencies directly used by APISIX impact APISIX's security.
  • Example: A known vulnerability is discovered in Nginx's HTTP/2 implementation which is part of OpenResty used by APISIX. If the deployed APISIX version uses a vulnerable Nginx version, attackers can exploit this vulnerability to cause a denial of service or potentially gain code execution on the APISIX server.
  • Impact: Denial of service, remote code execution, information disclosure, and other security breaches depending on the specific dependency vulnerability affecting APISIX.
  • Risk Severity: High to Critical (depending on the vulnerability severity)
  • Mitigation Strategies:
    • Regularly Update APISIX: Keep APISIX updated to the latest stable version, which typically includes updated versions of dependencies with security patches provided by the APISIX project.
    • Dependency Scanning: Implement automated dependency scanning tools to identify known vulnerabilities in APISIX's dependencies as part of APISIX security management.
    • Vulnerability Monitoring: Subscribe to security advisories and vulnerability databases related to OpenResty, Nginx, and Lua to stay informed about potential vulnerabilities affecting APISIX dependencies.
    • Patch Management: Establish a robust patch management process to quickly apply security updates for APISIX and its dependencies released by the APISIX project or upstream projects.