Input Validation / addJavascriptInterface Remote Code Execution

Description

AddJavaScriptInterface Remote Code Execution is a vulnerability in Android and mobile application that allows attackers to execute arbitrary code on the device. It is a type of Input Validation vulnerability, identified by the Common Weakness Enumeration (CWE) directory as CWE-494. It is also included in the OWASP Testing Guide, which provides further explanation of the vulnerability and how it works.

Risk

This vulnerability is considered a high risk, as it gives attackers unrestricted access to the victim’s device. It allows attackers to gain control of the device and its data, and can be used to launch malicious code or malware.

Solution

The vulnerability can be addressed by implementing input validation. When using addJavaScriptInterface, input must be validated to make sure that it does not contain malicious code. Furthermore, the use of addJavaScriptInterface should be restricted to trusted sources.

Example

WebView webView = (WebView) findViewById(R.id.webView);
// This line is vulnerable
webView.addJavascriptInterface(new MyJavascriptInterface(), "myjavascriptinterface");

In the above code, an instance of MyJavascriptInterface is passed to webView.addJavascriptInterface(). If the input is not validated, an attacker can pass malicious code and gain control of the device.