threat-modeling.md

Threat Model Analysis for marcuswestin/webviewjavascriptbridge

Threat: Unrestricted Native Function Access

Description: A malicious actor, potentially through compromised web content or by exploiting vulnerabilities in the bridge itself, can call native functions that were not intended to be publicly accessible from JavaScript. This could involve directly invoking internal functions or bypassing intended access controls within the native bridge implementation.

• Impact: Privilege escalation, allowing JavaScript code to execute native functions with elevated permissions. Unauthorized access to device resources like camera, microphone, location, contacts, and storage. Data breaches by accessing sensitive native data. Application compromise and potentially device compromise in severe cases.
• Affected Component: Native Bridge Function Dispatcher (the part of the native code that handles incoming messages and routes them to native function calls).
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Implement a strict whitelist of allowed native functions callable from JavaScript.
  • Implement robust authorization checks within each native function called from the bridge to verify permissions.
  • Follow the principle of least privilege when exposing native functions to the WebView.
  • Regularly audit native bridge code for vulnerabilities and enforce secure coding practices.

Threat: Exploitable Bugs in webviewjavascriptbridge Library or Custom Bridge Code

Description: Vulnerabilities may exist in the webviewjavascriptbridge library itself or in custom native or JavaScript code that extends or uses the bridge. These bugs could be exploited to bypass security measures, cause crashes, or gain unauthorized access. Examples include buffer overflows, injection vulnerabilities in message parsing, or logic errors in function dispatching. An attacker could trigger these vulnerabilities by sending specially crafted messages through the bridge.

• Impact: Application compromise, denial of service, privilege escalation, data breaches, or arbitrary code execution depending on the vulnerability.
• Affected Component: webviewjavascriptbridge library code (both JavaScript and Native components), and any custom bridge implementation code.
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Keep the webviewjavascriptbridge library updated to the latest version.
  • Thoroughly test and review custom bridge code for security vulnerabilities.
  • Follow secure coding practices during bridge implementation.
  • Utilize static and dynamic analysis tools to identify potential vulnerabilities in bridge code.
  • Implement robust error handling to prevent crashes and information leaks due to unexpected input.