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Attack Tree Analysis for marcuswestin/webviewjavascriptbridge

Objective: Compromise application that use given project by exploiting weaknesses or vulnerabilities within the project itself.

Attack Tree Visualization

Attack Tree Path: 1.1 Exploit Vulnerability in Message Handling (Native Side) [HR]

  • Description: This is a high-risk path because vulnerabilities in native code handling messages from the WebView can lead to direct code execution, bypassing many of the security mechanisms of the WebView sandbox. The attacker aims to send a specially crafted message that exploits a vulnerability in how the native code processes the message data.

Attack Tree Path: 1.1.1 Inject Malicious Message into Bridge (from WebView) [CN]

  • Description: This is a critical node because all attacks relying on the bridge require sending a message from the WebView. The attacker needs to be able to inject their malicious payload into the communication channel.
  • Attack Vectors:
    • 1.1.1.1 Compromise WebView Content (XSS, etc.): (Assumed prerequisite, outside the scope of this specific threat model, but essential). The attacker needs control over the JavaScript running in the WebView to send messages via the bridge. This could be achieved through Cross-Site Scripting (XSS), injecting malicious JavaScript into a legitimate website, or by hosting a malicious website that the user visits.
    • 1.1.1.2 Bypass Message Validation (if any) [HR]: If the bridge or native code performs any validation on incoming messages (e.g., checking message format, data types, or allowed origins), the attacker must bypass these checks.
      • 1.1.1.2.1 Identify Weak Validation Logic: The attacker analyzes the bridge's JavaScript and native code (if available) to find flaws in the validation process. This might involve looking for regular expressions that can be bypassed, insufficient type checking, or logic errors.
      • 1.1.1.2.2 Craft Message to Evade Validation: The attacker constructs a message that appears valid to the flawed validation logic but still carries the malicious payload. This often involves carefully manipulating string lengths, character encodings, or data types.

Attack Tree Path: 1.1.2 Trigger Vulnerability with Malicious Message [HR]

  • Description: Once the malicious message reaches the native code, the attacker needs to trigger the vulnerability. This is where the specific exploit payload comes into play.
  • Attack Vectors:
    • 1.1.2.1 Identify Vulnerable Native Handler [CN]: The attacker needs to determine which native function is called when a specific message is received. This might involve reverse engineering the native code, examining documentation, or observing the application's behavior.
    • 1.1.2.2 Craft Message to Exploit Vulnerability: This is the core of the exploit. The attacker crafts the message payload to exploit a specific vulnerability in the native handler. Examples include:
      • Buffer Overflow: Sending a string that is longer than the allocated buffer in the native code, overwriting adjacent memory. This can be used to overwrite return addresses or function pointers, redirecting execution flow.
      • Format String Vulnerability: If the native code uses a format string function (like printf in C/C++) with user-controlled input, the attacker can inject format specifiers (%x, %n, etc.) to read or write arbitrary memory locations.
      • Type Confusion: If the native code incorrectly casts the message data to a different type, the attacker might be able to manipulate object pointers or data structures.
      • Integer Overflow/Underflow: Causing an integer to wrap around, leading to unexpected behavior in calculations or memory allocations.
      • Use-After-Free: If the native code prematurely frees memory but continues to use a pointer to it, the attacker might be able to control the contents of that memory.
      • Logic Errors: Exploiting flaws in the handler's logic, such as incorrect bounds checking or improper handling of edge cases.

Attack Tree Path: 2.1 Intercept Messages Containing Sensitive Data [HR]

  • Description: This path focuses on eavesdropping on legitimate communication between the WebView and the native side to steal data.

    • 2.1.1 Compromise WebView Content (XSS, etc.): (Assumed prerequisite, outside the scope)

    • 2.1.2 Register Malicious Handler to Sniff Messages [CN] [HR]

      • Description: The attacker attempts to register a JavaScript handler that intercepts messages intended for other handlers. The success of this depends on the bridge's implementation and whether it allows overriding or intercepting existing handlers.
      • Attack Vectors:
        • 2.1.2.1.1 Overwrite Existing Handler [HR]: If the bridge allows re-registering a handler for the same message name, the attacker can replace a legitimate handler with their malicious one. This is a high-risk scenario.
        • 2.1.2.1.2 Register Handler with Broad Matching Criteria [HR]: If the bridge uses a pattern-matching system for routing messages, the attacker might register a handler with a very broad pattern that intercepts messages intended for other handlers. For example, registering a handler for "*" might intercept all messages.

    • 2.1.3 Exfiltrate Intercepted Data: Once the malicious handler receives the sensitive data, it needs to send it to the attacker. This could be done via an XMLHttpRequest, fetch, creating a hidden <iframe>, or other methods to send data to an attacker-controlled server.

Attack Tree Path: 2.2 Trick Native Side into Sending Sensitive Data [HR]

  • Description: This path involves manipulating the WebView to send crafted messages that trick the native side into revealing sensitive information.

    • 2.2.1 Compromise WebView Content (XSS, etc.): (Assumed prerequisite, outside the scope)

    • 2.2.2 Send Malicious Message Requesting Sensitive Data [CN]

      • Description: The attacker crafts a message that appears to be a legitimate request for data, but is designed to extract more information than intended or access data the WebView shouldn't have access to.
      • Attack Vectors:
        • 2.2.2.1 Bypass Input Validation (if any) [HR]: Similar to 1.1.1.2, the attacker needs to bypass any validation on the native side that checks the parameters of the request.
        • 2.2.2.2 Masquerade as Legitimate Request: The attacker crafts the message to look like a normal request that the native code expects, but with subtle modifications to extract more data. This relies on understanding the expected message format and semantics.

Attack Tree Path: 3.1 Compromise WebView Content (XSS, etc.):

  • Description: This path focuses on triggering unintended actions on the native side without necessarily achieving full code execution.
  • (Assumed prerequisite, outside the scope)

Attack Tree Path: 3.2 Send Malicious Message to Trigger Specific Native Function [CN] [HR]

  • Description: The attacker identifies a native function exposed through the bridge that can be abused to cause harm, even if it's not a direct code execution vulnerability.
    • Attack Vectors:
      • 3.2.1 Identify Target Native Function and Parameters: The attacker needs to understand which functions are exposed and what parameters they accept.
      • 3.2.2 Craft Message with Malicious Parameters: The attacker sends a message with carefully chosen parameters to trigger unintended behavior. Examples:
        • Causing a Denial of Service: If a function performs a resource-intensive operation, the attacker might send parameters that cause it to consume excessive resources, making the application unresponsive.
        • Modifying System Settings: If a function allows changing system settings, the attacker might try to alter them maliciously.
        • Deleting Files: If a function has file system access, the attacker might try to delete critical files.
        • Triggering Unintended Actions: Any function that performs an action based on user input could be a target.
      • 3.2.3 Bypass Input Validation/Authorization (if any) [HR]: The attacker must bypass any checks that would prevent the malicious parameters from being used.

Attack Tree Path: 4.1 Identify a Native Handler that Echoes Back Data to the WebView Unsafely [CN] [HR]

  • Description: This is a form of reflected XSS, but using the bridge as the vector. It's high-risk because it can bypass traditional XSS protections if the native code doesn't properly sanitize data.
  • Description: The attacker needs to find a native function that takes data from the WebView, processes it in some way, and then sends data back to the WebView. The vulnerability lies in the lack of proper escaping or sanitization of the returned data.
    • Attack Vectors:
      • 4.1.1 Analyze Native Code for Unescaped Output: The attacker examines the native code to find functions that return data to the WebView without proper HTML encoding or JavaScript escaping.
      • 4.1.2 Identify Handler that Receives Data from WebView and Returns it: The attacker observes the communication between the WebView and the native side to identify handlers that exhibit this behavior.

Attack Tree Path: 4.2 Send Malicious Message Containing JavaScript Payload

The attacker sends a message containing malicious JavaScript code (e.g., <script>alert('XSS')</script>).

Attack Tree Path: 4.3 Native Handler Injects Payload into WebView (Reflected XSS via the Bridge) [HR]

The native code, without proper sanitization, includes the attacker's payload in the response sent back to the WebView. The WebView then executes the injected JavaScript.

Attack Tree Path: 5.1 Send Large Number of Messages (Flood the Bridge)

  • Description: Overwhelm the bridge with a high volume of messages, potentially causing it to crash or become unresponsive.
    • Likelihood: Medium (depends on the bridge's robustness and rate limiting)
    • Impact: Medium (disrupts functionality, but doesn't necessarily lead to data compromise)
    • Effort: Low
    • Skill Level: Novice
    • Detection Difficulty: Easy (high traffic volume is easily detectable)

Attack Tree Path: 5.2 Send Malformed Messages to Crash the Bridge [HR]

  • Description: Exploit vulnerabilities in the message parsing logic to cause a crash or unexpected behavior.
    • Likelihood: Medium (depends on the quality of the parsing code)
    • Impact: Medium to High (can lead to denial of service, potentially code execution if a memory corruption vulnerability is triggered)
    • Effort: Medium
    • Skill Level: Intermediate to Advanced
    • Detection Difficulty: Medium (crashes are noticeable, but root cause analysis might be needed)
      • 5.2.1 Identify Vulnerability in Message Parsing (Native or JS Side) [CN]: This is crucial. The attacker needs to find a way to craft a message that causes an error during parsing. This could involve fuzzing or code review.
      • 5.2.2 Craft Malformed Message to Trigger Crash: The attacker creates a message that violates the expected format or contains unexpected data to trigger the vulnerability.

Attack Tree Path: 5.3 (Less Likely) Exploit Resource Exhaustion Vulnerability

  • Description: Find a way to make the bridge consume excessive resources (memory, CPU, file handles) without necessarily crashing it, leading to a denial of service.
    • Likelihood: Low
    • Impact: Medium
    • Effort: High
    • Skill Level: Advanced
    • Detection Difficulty: Hard (might require detailed performance monitoring)