mitigations.md

Mitigation Strategies Analysis for bang590/jspatch

Mitigation Strategy: Code Signing and Integrity Verification of the Patch Script

• Mitigation Strategy: Cryptographic Verification of JSPatch Script

  • Description:

    1. Generation: Before deploying a JSPatch script, generate a cryptographic signature using a strong algorithm (e.g., ECDSA with SHA-256 or better). This uses a private key (kept extremely secure) to create a signature unique to the script's content.
    2. Distribution: Distribute the script and its signature.
    3. Verification (App Side):
       • Before executing any code from the downloaded JSPatch script, the application retrieves the corresponding public key (securely embedded within the app).
       • The app uses the public key and the downloaded signature to verify the integrity of the downloaded script.
       • If verification fails, the script is immediately rejected. An error should be logged.
       • If verification succeeds, proceed (with other checks).
    4. Hashing (Recommended): Calculate a SHA-256 hash of the original script. Store this hash securely within the app. Before signature verification, calculate the hash of the downloaded script. Compare. Reject if they don't match.
    5. Secure Storage: After successful verification, store the script securely (e.g., encrypted storage, Keychain).

  • Threats Mitigated:

    • Threat: Malicious Script Injection (Severity: Critical) - Attacker modifies the script to inject malicious code.
    • Threat: Script Tampering (Severity: Critical) - Attacker alters the script's behavior.
    • Threat: Unauthorized Code Execution (Severity: Critical) - Unverified code runs within the app.

  • Impact:

    • Malicious Script Injection: Risk significantly reduced.
    • Script Tampering: Risk significantly reduced.
    • Unauthorized Code Execution: Risk significantly reduced.

  • Currently Implemented:

    • Hashing is implemented in NetworkManager.downloadPatch(). Expected hash in SecurityConstants.swift.
    • Basic HTTPS is used.

  • Missing Implementation:

    • Full digital signature verification is not implemented.
    • Secure storage after verification is not implemented.

Mitigation Strategy: Secure Delivery of the Patch Script

• Mitigation Strategy: HTTPS with Certificate Pinning for JSPatch Downloads

  • Description:

    1. HTTPS: All communication with the server hosting the JSPatch script must use HTTPS.
    2. Certificate Pinning:
       • Identify: Get the server's SSL/TLS certificate (or its public key).
       • Embed: Embed the certificate/public key in the app.
       • Verification: During HTTPS connection:
         • Get the server's certificate.
         • Compare it to the embedded pin.
         • If they match, proceed.
         • If they don't match, terminate the connection and log an error.
    3. Regular Updates: Update the pinned certificate/key in the app when the server's certificate is renewed.

  • Threats Mitigated:

    • Threat: Man-in-the-Middle (MitM) Attack (Severity: Critical) - Attacker intercepts and modifies the JSPatch script.
    • Threat: Eavesdropping (Severity: High) - Attacker listens to the communication (less critical for JSPatch than modification).

  • Impact:

    • MitM Attack: Risk significantly reduced.
    • Eavesdropping: Risk reduced (HTTPS provides encryption).

  • Currently Implemented:

    • Basic HTTPS is used.

  • Missing Implementation:

    • Certificate pinning is not implemented.

Mitigation Strategy: Strict Input Validation and Sanitization (within the JavaScript)

• Mitigation Strategy: Defensive JavaScript Programming within JSPatch Scripts

  • Description:

    1. Minimize API Surface (Objective-C): Carefully design the Objective-C interface exposed to JSPatch. Only expose the absolute minimum needed.
    2. Input Validation (Whitelist - in JavaScript): In the JavaScript code, strictly validate all input from:
       • User interaction.
       • External sources.
       • Arguments from Objective-C.
       • Use whitelisting: define allowed values and reject anything else.
    3. Output Encoding (in JavaScript): If the JavaScript interacts with the UI, use proper output encoding to prevent injection attacks (e.g., HTML escaping for UIWebView).
    4. Type Checking (in JavaScript): Use strict type checking.
    5. Regular Expressions (Careful Use - in JavaScript): If using regex, avoid ReDoS vulnerabilities.

  • Threats Mitigated:

    • Threat: Cross-Site Scripting (XSS) (Severity: High) - If the script interacts with a UIWebView.
    • Threat: Code Injection (Severity: High) - Through unvalidated input.
    • Threat: Logic Errors (Severity: Variable) - Due to improper input handling.

  • Impact:

    • XSS: Risk reduced.
    • Code Injection: Risk reduced.
    • Logic Errors: Risk reduced.

  • Currently Implemented:

    • Some basic input validation exists.

  • Missing Implementation:

    • Comprehensive, consistent whitelisting is not used.
    • Output encoding is not consistently used.
    • The Objective-C interface is too broad.

Mitigation Strategy: Principle of Least Privilege (Objective-C Side)

• Mitigation Strategy: Minimize Exposed Objective-C Interface for JSPatch

  • Description:

    1. Review: Review all Objective-C methods/properties exposed to JSPatch.
    2. Restrict: Remove access to anything not absolutely essential.
    3. Refactor: If needed, refactor Objective-C to create a limited, secure interface specifically for JSPatch.
    4. Documentation: Document the purpose and security of each exposed item.
    5. Regular Audits: Re-review the interface periodically.

  • Threats Mitigated:

    • Threat: Privilege Escalation (Severity: High) - Compromised script accesses sensitive data/functions.
    • Threat: Unauthorized Access (Severity: High) - Through exposed methods.

  • Impact:

    • Privilege Escalation: Risk significantly reduced.
    • Unauthorized Access: Risk significantly reduced.

  • Currently Implemented:

    • None. Wide range of methods exposed.

  • Missing Implementation:

    • Complete review and restriction needed.