mitigations.md

Mitigation Strategies Analysis for square/okhttp

Mitigation Strategy: Regularly Update OkHttp

• Description:

  1. Identify Current OkHttp Version: Check your project's dependency management file (e.g., build.gradle) to determine the currently used OkHttp version.
  2. Check for Latest Stable Version: Visit the official OkHttp repository (https://github.com/square/okhttp/releases) or Maven Central/Gradle Plugin Portal to find the latest stable release version.
  3. Update Dependency Version: Modify your dependency management file to use the latest stable OkHttp version.
  4. Test Application: Thoroughly test your application after updating OkHttp, focusing on network requests made using OkHttp.
  5. Establish Update Cadence: Create a process for regularly checking for and applying OkHttp updates.

  • Threats Mitigated:

    • Exploitation of Known Vulnerabilities (High Severity): Outdated OkHttp versions can contain known security vulnerabilities that attackers can exploit.
    • Zero-Day Vulnerabilities (Medium Severity): Staying updated reduces the window of exposure to newly discovered zero-day vulnerabilities in OkHttp.

  • Impact:

    • Exploitation of Known Vulnerabilities: High Risk Reduction - Directly patches known OkHttp vulnerabilities.
    • Zero-Day Vulnerabilities: Medium Risk Reduction - Reduces exposure time to new OkHttp vulnerabilities.

  • Currently Implemented:

    • Partially implemented. OkHttp updates are generally performed during major release cycles. Version is managed in build.gradle file.

  • Missing Implementation:

    • Lack of a defined process for regular (e.g., monthly) checks specifically for OkHttp updates.
    • No automated alerts for new OkHttp releases or security advisories.

Mitigation Strategy: Enforce TLS 1.2 or Higher in OkHttp

• Description:

  1. Create a ConnectionSpec: Instantiate a ConnectionSpec object.
  2. Configure TLS Versions: Use ConnectionSpec.Builder to specify TlsVersion.TLS_1_2 and TlsVersion.TLS_1_3 (if desired) in the tlsVersions() method.
  3. Configure Cipher Suites (Optional but Recommended): Use ConnectionSpec.Builder to specify secure cipher suites in the cipherSuites() method.
  4. Apply ConnectionSpec to OkHttpClient: When building your OkHttpClient, use the connectionSpecs() method to apply the created ConnectionSpec list.

  • Threats Mitigated:

    • Downgrade Attacks (High Severity): Prevents attackers from forcing OkHttp connections to use older, weaker TLS versions like TLS 1.0 or TLS 1.1.
    • Cipher Suite Weaknesses (Medium Severity): Explicitly configuring cipher suites in OkHttp further reduces the risk of using weak or compromised ciphers.

  • Impact:

    • Downgrade Attacks: High Risk Reduction - Directly prevents downgrade attacks for OkHttp connections.
    • Cipher Suite Weaknesses: Medium Risk Reduction - Reduces risk related to cipher suite vulnerabilities in OkHttp.

  • Currently Implemented:

    • Not currently implemented. Application relies on OkHttp's default ConnectionSpec.

  • Missing Implementation:

    • ConnectionSpec configuration is not explicitly set in the OkHttpClient initialization within the project.
    • No explicit configuration of cipher suites within OkHttp client setup.

Mitigation Strategy: Enable Hostname Verification in OkHttp

• Description:

  1. Ensure Default OkHttpClient Behavior: Hostname verification is enabled by default in OkHttp.
  2. Avoid Disabling Hostname Verification: Do not use .hostnameVerifier(HostnameVerifier.ALLOW_ALL) or similar methods in your OkHttpClient configuration unless absolutely necessary for controlled testing.
  3. Review Custom SSL Configurations: If using custom SSLSocketFactory or TrustManager with OkHttp, verify they maintain hostname verification.

  • Threats Mitigated:

    • Man-in-the-Middle (MITM) Attacks (High Severity): Hostname verification in OkHttp prevents MITM attacks by ensuring the application connects to the intended server and not a malicious impersonator.

  • Impact:

    • Man-in-the-Middle (MITM) Attacks: High Risk Reduction - Crucial for preventing MITM attacks when using OkHttp.

  • Currently Implemented:

    • Implemented by default as standard OkHttpClient instantiation is used.

  • Missing Implementation:

    • No explicit code reviews to confirm hostname verification is always enabled in OkHttp client configurations, especially if custom SSL handling is ever introduced.

Mitigation Strategy: Implement Certificate Pinning in OkHttp (for critical connections)

• Description:

  1. Choose Pinning Strategy: Decide between certificate or public key pinning for OkHttp.
  2. Obtain Server Certificate/Public Key: Retrieve the server's certificate or public key for the target host(s) used with OkHttp.
  3. Create a CertificatePinner: Instantiate a CertificatePinner.Builder.
  4. Add Pins to CertificatePinner: Use CertificatePinner.Builder.add() to add pins for the target hostname(s), specifying the SHA-256 hash of the certificate or public key.
  5. Apply CertificatePinner to OkHttpClient: When building your OkHttpClient, use the certificatePinner() method to apply the created CertificatePinner.
  6. Pin Backup Strategy & Rotation Plan: Develop a backup pinning strategy and a plan for rotating pins when server certificates are updated to avoid service disruption when using OkHttp.

  • Threats Mitigated:

    • Man-in-the-Middle (MITM) Attacks due to Compromised Certificate Authorities (High Severity): OkHttp certificate pinning mitigates MITM attacks even if a CA is compromised.
    • Rogue CAs (High Severity): Protects OkHttp connections against attacks involving rogue or malicious Certificate Authorities.

  • Impact:

    • Man-in-the-Middle (MITM) Attacks due to Compromised CAs: High Risk Reduction - Significantly reduces risk from CA compromise for OkHttp connections.
    • Rogue CAs: High Risk Reduction - Eliminates trust in potentially rogue CAs for OkHttp connections.

  • Currently Implemented:

    • Not currently implemented. Certificate pinning is not used in OkHttp configurations.

  • Missing Implementation:

    • Certificate pinning is not configured for any OkHttpClient instances within the project.
    • No plan for implementing and managing certificate pinning for critical backend services accessed via OkHttp.

Mitigation Strategy: Control Redirect Handling in OkHttp

• Description:

  1. Review Default Redirect Behavior: Understand OkHttp's default behavior for handling HTTP redirects (both regular and SSL redirects).
  2. Customize Redirect Following (If Needed): If stricter control is required, use OkHttpClient.Builder methods like followRedirects(boolean) and followSslRedirects(boolean) to disable or customize redirect following.
  3. Implement Custom Redirect Logic (Advanced): For fine-grained control, implement a custom Interceptor that intercepts redirect responses and applies specific logic to determine whether to follow the redirect based on destination URL or other criteria.

  • Threats Mitigated:

    • Open Redirect Vulnerabilities (Medium Severity): Uncontrolled redirect handling in OkHttp could potentially be exploited for open redirect vulnerabilities if the application blindly follows redirects to untrusted destinations.

  • Impact:

    • Open Redirect Vulnerabilities: Medium Risk Reduction - Reduces the risk of open redirect vulnerabilities arising from OkHttp's redirect handling.

  • Currently Implemented:

    • Default OkHttp redirect handling is used. No custom redirect control is implemented.

  • Missing Implementation:

    • No explicit review or customization of OkHttp's redirect handling behavior has been performed.
    • No custom interceptor for redirect control is implemented.

Mitigation Strategy: Secure Logging Practices for OkHttp Interceptors

• Description:

  1. Review OkHttp Logging Interceptors: Examine your OkHttp configuration for any HttpLoggingInterceptor instances.
  2. Minimize Logging Level in Production: Set the logging level of HttpLoggingInterceptor to NONE, BASIC, or HEADERS in production. Avoid BODY or BODY_STAR levels in production to prevent excessive logging of potentially sensitive data.
  3. Redact Sensitive Data in Logging Interceptors (If Needed): If BODY logging is necessary for debugging, create custom interceptors to redact or sanitize sensitive data from request/response bodies before they are logged by OkHttp.

  • Threats Mitigated:

    • Exposure of Sensitive Information in Logs (High Severity): Logging sensitive data by OkHttp interceptors can lead to security breaches if logs are compromised.

  • Impact:

    • Exposure of Sensitive Information in Logs: High Risk Reduction - Significantly reduces the risk of sensitive data exposure through OkHttp logs.

  • Currently Implemented:

    • HttpLoggingInterceptor is used in development with BODY level.
    • In production, logging level is set to HEADERS.

  • Missing Implementation:

    • No explicit redaction of sensitive data in OkHttp logging, even when BODY logging is used in development.
    • No automated checks to ensure minimal logging levels are enforced in production OkHttp configurations.

Mitigation Strategy: Configure Connection Pool Limits in OkHttp

• Description:

  1. Review Default Connection Pool: Understand OkHttp's default connection pool settings.
  2. Configure ConnectionPool: Create a ConnectionPool instance and configure its maxIdleConnections() and keepAliveDuration() parameters based on your application's needs and server capabilities.
  3. Apply ConnectionPool to OkHttpClient: Use the connectionPool() method when building your OkHttpClient to apply the configured ConnectionPool.

  • Threats Mitigated:

    • Resource Exhaustion/DoS (Medium Severity): Unbounded connection pooling in OkHttp could potentially contribute to resource exhaustion or DoS if an attacker can trigger excessive connection creation.

  • Impact:

    • Resource Exhaustion/DoS: Medium Risk Reduction - Helps prevent resource exhaustion related to excessive OkHttp connection pooling.

  • Currently Implemented:

    • Default OkHttp connection pool settings are used. No custom configuration is in place.

  • Missing Implementation:

    • No explicit configuration of ConnectionPool limits in OkHttp client setup.
    • No performance testing or analysis to determine optimal connection pool settings for the application's usage patterns.

Mitigation Strategy: Set Timeouts Appropriately in OkHttp

• Description:

  1. Configure Connect Timeout: Set an appropriate connectTimeout() on your OkHttpClient.Builder to limit the time OkHttp will wait to establish a connection to a server.
  2. Configure Read Timeout: Set an appropriate readTimeout() to limit the time OkHttp will wait for data to be received from the server after a connection is established.
  3. Configure Write Timeout: Set an appropriate writeTimeout() to limit the time OkHttp will wait to send data to the server.
  4. Review Timeout Values: Regularly review and adjust timeout values based on network conditions and expected server response times.

  • Threats Mitigated:

    • Denial of Service (DoS) due to Slowloris-like Attacks (Medium Severity): Timeouts in OkHttp can help mitigate slowloris-like attacks where attackers attempt to keep connections open indefinitely, exhausting server resources.
    • Application Hangs/Unresponsiveness (Medium Severity): Timeouts prevent the application from hanging indefinitely due to slow or unresponsive servers when using OkHttp.

  • Impact:

    • Denial of Service (DoS) due to Slowloris-like Attacks: Medium Risk Reduction - Helps mitigate slowloris-like attacks by limiting connection duration.
    • Application Hangs/Unresponsiveness: Medium Risk Reduction - Improves application robustness and prevents hangs due to network issues when using OkHttp.

  • Currently Implemented:

    • Default timeouts are used in OkHttpClient configuration.

  • Missing Implementation:

    • Timeouts are not explicitly configured or tuned for specific use cases or network environments.
    • No process for regularly reviewing and adjusting OkHttp timeout values.