MASTG-TEST-0075: Testing Custom URL Schemes

Overview

Static Analysis

There are a couple of things that we can do using static analysis. In the next sections we will see the following:

• Testing custom URL schemes registration
• Testing application query schemes registration
• Testing URL handling and validation
• Testing URL requests to other apps
• Testing for deprecated methods

Testing Custom URL Schemes Registration

The first step to test custom URL schemes is finding out whether an application registers any protocol handlers.

If you have the original source code and want to view registered protocol handlers, simply open the project in Xcode, go to the Info tab and open the URL Types section as presented in the screenshot below:

Also in Xcode you can find this by searching for the CFBundleURLTypes key in the app’s Info.plist file (example from iGoat-Swift):

<key>CFBundleURLTypes</key>
<array>
    <dict>
        <key>CFBundleURLName</key>
        <string>com.iGoat.myCompany</string>
        <key>CFBundleURLSchemes</key>
        <array>
            <string>iGoat</string>
        </array>
    </dict>
</array>

In a compiled application (or IPA), registered protocol handlers are found in the file Info.plist in the app bundle's root folder. Open it and search for the CFBundleURLSchemes key, if present, it should contain an array of strings (example from iGoat-Swift):

grep -A 5 -nri urlsch Info.plist
Info.plist:45:    <key>CFBundleURLSchemes</key>
Info.plist-46-    <array>
Info.plist-47-        <string>iGoat</string>
Info.plist-48-    </array>

Once the URL scheme is registered, other apps can open the app that registered the scheme, and pass parameters by creating appropriately formatted URLs and opening them with the UIApplication openURL:options:completionHandler: method.

Note from the App Programming Guide for iOS:

If more than one third-party app registers to handle the same URL scheme, there is currently no process for determining which app will be given that scheme.

This could lead to a URL scheme hijacking attack (see page 136 in [#thiel2]).

Testing Application Query Schemes Registration

Before calling the openURL:options:completionHandler: method, apps can call canOpenURL: to verify that the target app is available. However, as this method was being used by malicious app as a way to enumerate installed apps, from iOS 9.0 the URL schemes passed to it must be also declared by adding the LSApplicationQueriesSchemes key to the app's Info.plist file and an array of up to 50 URL schemes.

<key>LSApplicationQueriesSchemes</key>
    <array>
        <string>url_scheme1</string>
        <string>url_scheme2</string>
    </array>

canOpenURL will always return NO for undeclared schemes, whether or not an appropriate app is installed. However, this restriction only applies to canOpenURL.

The openURL:options:completionHandler: method will still open any URL scheme, even if the LSApplicationQueriesSchemes array was declared, and return YES / NO depending on the result.

As an example, Telegram declares in its Info.plist these Queries Schemes, among others:

    <key>LSApplicationQueriesSchemes</key>
    <array>
        <string>dbapi-3</string>
        <string>instagram</string>
        <string>googledrive</string>
        <string>comgooglemaps-x-callback</string>
        <string>foursquare</string>
        <string>here-location</string>
        <string>yandexmaps</string>
        <string>yandexnavi</string>
        <string>comgooglemaps</string>
        <string>youtube</string>
        <string>twitter</string>
        ...

Testing URL Handling and Validation

In order to determine how a URL path is built and validated, if you have the original source code, you can search for the following methods:

• application:didFinishLaunchingWithOptions: method or application:will-FinishLaunchingWithOptions:: verify how the decision is made and how the information about the URL is retrieved.
• application:openURL:options:: verify how the resource is being opened, i.e. how the data is being parsed, verify the options, especially if access by the calling app (sourceApplication) should be allowed or denied. The app might also need user permission when using the custom URL scheme.

In Telegram you will find four different methods being used:

func application(_ application: UIApplication, open url: URL, sourceApplication: String?) -> Bool {
    self.openUrl(url: url)
    return true
}

func application(_ application: UIApplication, open url: URL, sourceApplication: String?,
annotation: Any) -> Bool {
    self.openUrl(url: url)
    return true
}

func application(_ app: UIApplication, open url: URL,
options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
    self.openUrl(url: url)
    return true
}

func application(_ application: UIApplication, handleOpen url: URL) -> Bool {
    self.openUrl(url: url)
    return true
}

We can observe some things here:

• The app implements also deprecated methods like application:handleOpenURL: and application:openURL:sourceApplication:annotation:.
• The source application is not being verified in any of those methods.
• All of them call a private openUrl method. You can inspect it to learn more about how the URL request is handled.

Testing URL Requests to Other Apps

The method openURL:options:completionHandler: and the deprecated openURL: method of UIApplication are responsible for opening URLs (i.e. to send requests / make queries to other apps) that may be local to the current app or it may be one that must be provided by a different app. If you have the original source code you can search directly for usages of those methods.

Additionally, if you are interested into knowing if the app is querying specific services or apps, and if the app is well-known, you can also search for common URL schemes online and include them in your greps. For example, a quick Google search reveals:

Apple Music - music:// or musics:// or audio-player-event://
Calendar - calshow:// or x-apple-calevent://
Contacts - contacts://
Diagnostics - diagnostics:// or diags://
GarageBand - garageband://
iBooks - ibooks:// or itms-books:// or itms-bookss://
Mail - message:// or mailto://emailaddress
Messages - sms://phonenumber
Notes - mobilenotes://
...

We search for this method in the Telegram source code, this time without using Xcode, just with egrep:

$ egrep -nr "open.*options.*completionHandler" ./Telegram-iOS/

./AppDelegate.swift:552: return UIApplication.shared.open(parsedUrl,
    options: [UIApplicationOpenURLOptionUniversalLinksOnly: true as NSNumber],
    completionHandler: { value in
./AppDelegate.swift:556: return UIApplication.shared.open(parsedUrl,
    options: [UIApplicationOpenURLOptionUniversalLinksOnly: true as NSNumber],
    completionHandler: { value in

If we inspect the results we will see that openURL:options:completionHandler: is actually being used for universal links, so we have to keep searching. For example, we can search for openURL(:

$ egrep -nr "openURL\(" ./Telegram-iOS/

./ApplicationContext.swift:763:  UIApplication.shared.openURL(parsedUrl)
./ApplicationContext.swift:792:  UIApplication.shared.openURL(URL(
                                        string: "https://telegram.org/deactivate?phone=\(phone)")!
                                 )
./AppDelegate.swift:423:         UIApplication.shared.openURL(url)
./AppDelegate.swift:538:         UIApplication.shared.openURL(parsedUrl)
...

If we inspect those lines we will see how this method is also being used to open "Settings" or to open the "App Store Page".

When just searching for :// we see:

if documentUri.hasPrefix("file://"), let path = URL(string: documentUri)?.path {
if !url.hasPrefix("mt-encrypted-file://?") {
guard let dict = TGStringUtils.argumentDictionary(inUrlString: String(url[url.index(url.startIndex,
    offsetBy: "mt-encrypted-file://?".count)...])) else {
parsedUrl = URL(string: "https://\(url)")
if let url = URL(string: "itms-apps://itunes.apple.com/app/id\(appStoreId)") {
} else if let url = url as? String, url.lowercased().hasPrefix("tg://") {
[[WKExtension sharedExtension] openSystemURL:[NSURL URLWithString:[NSString
    stringWithFormat:@"tel://%@", userHandle.data]]];

After combining the results of both searches and carefully inspecting the source code we find the following piece of code:

openUrl: { url in
            var parsedUrl = URL(string: url)
            if let parsed = parsedUrl {
                if parsed.scheme == nil || parsed.scheme!.isEmpty {
                    parsedUrl = URL(string: "https://\(url)")
                }
                if parsed.scheme == "tg" {
                    return
                }
            }

            if let parsedUrl = parsedUrl {
                UIApplication.shared.openURL(parsedUrl)

Before opening a URL, the scheme is validated, "https" will be added if necessary and it won't open any URL with the "tg" scheme. When ready it will use the deprecated openURL method.

If only having the compiled application (IPA) you can still try to identify which URL schemes are being used to query other apps:

• Check if LSApplicationQueriesSchemes was declared or search for common URL schemes.
• Also use the string :// or build a regular expression to match URLs as the app might not be declaring some schemes.

You can do that by first verifying that the app binary contains those strings by e.g. using unix strings command:

strings <yourapp> | grep "someURLscheme://"

or even better, use radare2's iz/izz command or rafind2, both will find strings where the unix strings command won't. Example from iGoat-Swift:

$ r2 -qc izz~iGoat:// iGoat-Swift
37436 0x001ee610 0x001ee610  23  24 (4.__TEXT.__cstring) ascii iGoat://?contactNumber=

Testing for Deprecated Methods

Search for deprecated methods like:

• application:handleOpenURL:
• openURL:
• application:openURL:sourceApplication:annotation:

For example, here we find those three:

$ rabin2 -zzq Telegram\ X.app/Telegram\ X | grep -i "openurl"

0x1000d9e90 31 30 UIApplicationOpenURLOptionsKey
0x1000dee3f 50 49 application:openURL:sourceApplication:annotation:
0x1000dee71 29 28 application:openURL:options:
0x1000dee8e 27 26 application:handleOpenURL:
0x1000df2c9 9 8 openURL:
0x1000df766 12 11 canOpenURL:
0x1000df772 35 34 openURL:options:completionHandler:
...

Dynamic Analysis

Once you've identified the custom URL schemes the app has registered, there are several methods that you can use to test them:

• Performing URL requests
• Identifying and hooking the URL handler method
• Testing URL schemes source validation
• Fuzzing URL schemes

Performing URL Requests

Using Safari

To quickly test one URL scheme you can open the URLs on Safari and observe how the app behaves. For example, if you write tel://123456789 in the address bar of Safari, a pop up will appear with the telephone number and the options "Cancel" and "Call". If you press "Call" it will open the Phone app and directly make the call.

You may also know already about pages that trigger custom URL schemes, you can just navigate normally to those pages and Safari will automatically ask when it finds a custom URL scheme.

Using the Notes App

As already seen in "Triggering Universal Links", you may use the Notes app and long press the links you've written in order to test custom URL schemes. Remember to exit the editing mode in order to be able to open them. Note that you can click or long press links including custom URL schemes only if the app is installed, if not they won't be highlighted as clickable links.

Using Frida

If you simply want an app to open the URL scheme you can do it using Frida. Example using iGoat-Swift:

$ frida -U iGoat-Swift

[iPhone::iGoat-Swift]-> function openURL(url) {
                            var UIApplication = ObjC.classes.UIApplication.sharedApplication();
                            var toOpen = ObjC.classes.NSURL.URLWithString_(url);
                            return UIApplication.openURL_(toOpen);
                        }
[iPhone::iGoat-Swift]-> openURL("tel://234234234")
true

In this example from Frida CodeShare the author uses the non-public API LSApplication Workspace.openSensitiveURL:withOptions: to open the URLs (from the SpringBoard app):

function openURL(url) {
    var w = ObjC.classes.LSApplicationWorkspace.defaultWorkspace();
    var toOpen = ObjC.classes.NSURL.URLWithString_(url);
    return w.openSensitiveURL_withOptions_(toOpen, null);
}

Note that the use of non-public APIs is not permitted on the App Store, that's why we don't even test these but we are allowed to use them for our dynamic analysis.

Identifying and Hooking the URL Handler Method

If you can't look into the original source code you will have to find out yourself which method does the app use to handle the URL scheme requests that it receives. You cannot know if it is an Objective-C method or a Swift one, or even if the app is using a deprecated one.

Crafting the Link Yourself and Letting Safari Open It

For this we will use the ObjC method observer from Frida CodeShare, which is an extremely handy script that allows you to quickly observe any collection of methods or classes just by providing a simple pattern.

In this case we are interested into all methods from the iGoat-Swift app containing "openURL", therefore our pattern will be *[* *openURL*]:

• The first asterisk will match all instance - and class + methods.
• The second matches all Objective-C classes.
• The third and forth allow to match any method containing the string openURL.

$ frida -U iGoat-Swift --codeshare mrmacete/objc-method-observer

[iPhone::iGoat-Swift]-> observeSomething("*[* *openURL*]");
Observing  -[_UIDICActivityItemProvider activityViewController:openURLAnnotationForActivityType:]
Observing  -[CNQuickActionsManager _openURL:]
Observing  -[SUClientController openURL:]
Observing  -[SUClientController openURL:inClientWithIdentifier:]
Observing  -[FBSSystemService openURL:application:options:clientPort:withResult:]
Observing  -[iGoat_Swift.AppDelegate application:openURL:options:]
Observing  -[PrefsUILinkLabel openURL:]
Observing  -[UIApplication openURL:]
Observing  -[UIApplication _openURL:]
Observing  -[UIApplication openURL:options:completionHandler:]
Observing  -[UIApplication openURL:withCompletionHandler:]
Observing  -[UIApplication _openURL:originatingView:completionHandler:]
Observing  -[SUApplication application:openURL:sourceApplication:annotation:]
...

The list is very long and includes the methods we have already mentioned. If we trigger now one URL scheme, for example "igoat://" from Safari and accept to open it in the app we will see the following:

[iPhone::iGoat-Swift]-> (0x1c4038280)  -[iGoat_Swift.AppDelegate application:openURL:options:]
application: <UIApplication: 0x101d0fad0>
openURL: igoat://
options: {
    UIApplicationOpenURLOptionsOpenInPlaceKey = 0;
    UIApplicationOpenURLOptionsSourceApplicationKey = "com.apple.mobilesafari";
}
0x18b5030d8 UIKit!__58-[UIApplication _applicationOpenURLAction:payload:origin:]_block_invoke
0x18b502a94 UIKit!-[UIApplication _applicationOpenURLAction:payload:origin:]
...
0x1817e1048 libdispatch.dylib!_dispatch_client_callout
0x1817e86c8 libdispatch.dylib!_dispatch_block_invoke_direct$VARIANT$mp
0x18453d9f4 FrontBoardServices!__FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__
0x18453d698 FrontBoardServices!-[FBSSerialQueue _performNext]
RET: 0x1

Now we know that:

• The method -[iGoat_Swift.AppDelegate application:openURL:options:] gets called. As we have seen before, it is the recommended way and it is not deprecated.
• It receives our URL as a parameter: igoat://.
• We also can verify the source application: com.apple.mobilesafari.
• We can also know from where it was called, as expected from -[UIApplication _applicationOpenURLAction:payload:origin:].
• The method returns 0x1 which means YES (the delegate successfully handled the request).

The call was successful and we see now that the iGoat-Swift app was open:

Notice that we can also see that the caller (source application) was Safari if we look in the upper-left corner of the screenshot.

Dynamically Opening the Link from the App Itself

It is also interesting to see which other methods get called on the way. To change the result a little bit we will call the same URL scheme from the iGoat-Swift app itself. We will use again ObjC method observer and the Frida REPL:

$ frida -U iGoat-Swift --codeshare mrmacete/objc-method-observer

[iPhone::iGoat-Swift]-> function openURL(url) {
                            var UIApplication = ObjC.classes.UIApplication.sharedApplication();
                            var toOpen = ObjC.classes.NSURL.URLWithString_(url);
                            return UIApplication.openURL_(toOpen);
                        }

[iPhone::iGoat-Swift]-> observeSomething("*[* *openURL*]");
[iPhone::iGoat-Swift]-> openURL("iGoat://?contactNumber=123456789&message=hola")

(0x1c409e460)  -[__NSXPCInterfaceProxy__LSDOpenProtocol openURL:options:completionHandler:]
openURL: iGoat://?contactNumber=123456789&message=hola
options: nil
completionHandler: <__NSStackBlock__: 0x16fc89c38>
0x183befbec MobileCoreServices!-[LSApplicationWorkspace openURL:withOptions:error:]
0x10ba6400c
...
RET: nil

...

(0x101d0fad0)  -[UIApplication openURL:]
openURL: iGoat://?contactNumber=123456789&message=hola
0x10a610044
...
RET: 0x1

true
(0x1c4038280)  -[iGoat_Swift.AppDelegate application:openURL:options:]
application: <UIApplication: 0x101d0fad0>
openURL: iGoat://?contactNumber=123456789&message=hola
options: {
    UIApplicationOpenURLOptionsOpenInPlaceKey = 0;
    UIApplicationOpenURLOptionsSourceApplicationKey = "OWASP.iGoat-Swift";
}
0x18b5030d8 UIKit!__58-[UIApplication _applicationOpenURLAction:payload:origin:]_block_invoke
0x18b502a94 UIKit!-[UIApplication _applicationOpenURLAction:payload:origin:]
...
RET: 0x1

The output is truncated for better readability. This time you see that UIApplicationOpenURLOptionsSourceApplicationKey has changed to OWASP.iGoat-Swift, which makes sense. In addition, a long list of openURL-like methods were called. Considering this information can be very useful for some scenarios as it will help you to decide what you next steps will be, e.g. which method you will hook or tamper with next.

Opening a Link by Navigating to a Page and Letting Safari Open It

You can now test the same situation when clicking on a link contained on a page. Safari will identify and process the URL scheme and choose which action to execute. Opening this link "https://telegram.me/fridadotre" will trigger this behavior.

First of all we let frida-trace generate the stubs for us:

$ frida-trace -U Telegram -m "*[* *restorationHandler*]" -i "*open*Url*"
    -m "*[* *application*URL*]" -m "*[* openURL]"

...
7310 ms  -[UIApplication _applicationOpenURLAction: 0x1c44ff900 payload: 0x10c5ee4c0 origin: 0x0]
7311 ms     | -[AppDelegate application: 0x105a59980 openURL: 0x1c46ebb80 options: 0x1c0e222c0]
7312 ms     | $S10TelegramUI15openExternalUrl7account7context3url05forceD016presentationData
            18applicationContext20navigationController12dismissInputy0A4Core7AccountC_AA14Open
            URLContextOSSSbAA012PresentationK0CAA0a11ApplicationM0C7Display010NavigationO0CSgyyctF()

Now we can simply modify by hand the stubs we are interested in:

• The Objective-C method application:openURL:options::

  // __handlers__/__AppDelegate_application_openUR_3679fadc.js
  
  onEnter: function (log, args, state) {
      log("-[AppDelegate application: " + args[2] +
                  " openURL: " + args[3] + " options: " + args[4] + "]");
      log("\tapplication :" + ObjC.Object(args[2]).toString());
      log("\topenURL :" + ObjC.Object(args[3]).toString());
      log("\toptions :" + ObjC.Object(args[4]).toString());
  },
  

• The Swift method $S10TelegramUI15openExternalUrl...:

  // __handlers__/TelegramUI/_S10TelegramUI15openExternalUrl7_b1a3234e.js
  
  onEnter: function (log, args, state) {
  
      log("TelegramUI.openExternalUrl(account, url, presentationData," +
                  "applicationContext, navigationController, dismissInput)");
      log("\taccount: " + ObjC.Object(args[1]).toString());
      log("\turl: " + ObjC.Object(args[2]).toString());
      log("\tpresentationData: " + args[3]);
      log("\tapplicationContext: " + ObjC.Object(args[4]).toString());
      log("\tnavigationController: " + ObjC.Object(args[5]).toString());
  },
  

The next time we run it, we see the following output:

$ frida-trace -U Telegram -m "*[* *restorationHandler*]" -i "*open*Url*"
    -m "*[* *application*URL*]" -m "*[* openURL]"

  8144 ms  -[UIApplication _applicationOpenURLAction: 0x1c44ff900 payload: 0x10c5ee4c0 origin: 0x0]
  8145 ms     | -[AppDelegate application: 0x105a59980 openURL: 0x1c46ebb80 options: 0x1c0e222c0]
  8145 ms     |     application: <Application: 0x105a59980>
  8145 ms     |     openURL: tg://resolve?domain=fridadotre
  8145 ms     |     options :{
                        UIApplicationOpenURLOptionsOpenInPlaceKey = 0;
                        UIApplicationOpenURLOptionsSourceApplicationKey = "com.apple.mobilesafari";
                    }
  8269 ms     |    | TelegramUI.openExternalUrl(account, url, presentationData,
                                        applicationContext, navigationController, dismissInput)
  8269 ms     |    |    account: nil
  8269 ms     |    |    url: tg://resolve?domain=fridadotre
  8269 ms     |    |    presentationData: 0x1c4c51741
  8269 ms     |    |    applicationContext: nil
  8269 ms     |    |    navigationController: TelegramUI.PresentationData
  8274 ms     | -[UIApplication applicationOpenURL:0x1c46ebb80]

There you can observe the following:

• It calls application:openURL:options: from the app delegate as expected.
• The source application is Safari ("com.apple.mobilesafari").
• application:openURL:options: handles the URL but does not open it, it calls TelegramUI.openExternalUrl for that.
• The URL being opened is tg://resolve?domain=fridadotre.
• It uses the tg:// custom URL scheme from Telegram.

It is interesting to see that if you navigate again to "https://telegram.me/fridadotre", click on cancel and then click on the link offered by the page itself ("Open in the Telegram app"), instead of opening via custom URL scheme it will open via universal links.

You can try this while tracing both methods:

$ frida-trace -U Telegram -m "*[* *restorationHandler*]" -m "*[* *application*openURL*options*]"

// After clicking "Open" on the pop-up

 16374 ms  -[AppDelegate application :0x10556b3c0 openURL :0x1c4ae0080 options :0x1c7a28400]
 16374 ms   application :<Application: 0x10556b3c0>
 16374 ms   openURL :tg://resolve?domain=fridadotre
 16374 ms   options :{
    UIApplicationOpenURLOptionsOpenInPlaceKey = 0;
    UIApplicationOpenURLOptionsSourceApplicationKey = "com.apple.mobilesafari";
}

// After clicking "Cancel" on the pop-up and "OPEN" in the page

406575 ms  -[AppDelegate application:0x10556b3c0 continueUserActivity:0x1c063d0c0
                restorationHandler:0x16f27a898]
406575 ms  application:<Application: 0x10556b3c0>
406575 ms  continueUserActivity:<NSUserActivity: 0x1c063d0c0>
406575 ms       webpageURL:https://telegram.me/fridadotre
406575 ms       activityType:NSUserActivityTypeBrowsingWeb
406575 ms       userInfo:{
}
406575 ms  restorationHandler:<__NSStackBlock__: 0x16f27a898>

Testing for Deprecated Methods

Search for deprecated methods like:

• application:handleOpenURL:
• openURL:
• application:openURL:sourceApplication:annotation:

You may simply use frida-trace for this, to see if any of those methods are being used.

Testing URL Schemes Source Validation

A way to discard or confirm validation could be by hooking typical methods that might be used for that. For example isEqualToString::

// - (BOOL)isEqualToString:(NSString *)aString;

var isEqualToString = ObjC.classes.NSString["- isEqualToString:"];

Interceptor.attach(isEqualToString.implementation, {
  onEnter: function(args) {
    var message = ObjC.Object(args[2]);
    console.log(message)
  }
});

If we apply this hook and call the URL scheme again:

$ frida -U iGoat-Swift

[iPhone::iGoat-Swift]-> var isEqualToString = ObjC.classes.NSString["- isEqualToString:"];

                    Interceptor.attach(isEqualToString.implementation, {
                      onEnter: function(args) {
                        var message = ObjC.Object(args[2]);
                        console.log(message)
                      }
                    });
{}
[iPhone::iGoat-Swift]-> openURL("iGoat://?contactNumber=123456789&message=hola")
true
nil

Nothing happens. This tells us already that this method is not being used for that as we cannot find any app-package-looking string like OWASP.iGoat-Swift or com.apple.mobilesafari between the hook and the text of the tweet. However, consider that we are just probing one method, the app might be using other approach for the comparison.

Fuzzing URL Schemes

If the app parses parts of the URL, you can also perform input fuzzing to detect memory corruption bugs.

What we have learned above can be now used to build your own fuzzer on the language of your choice, e.g. in Python and call the openURL using Frida's RPC. That fuzzer should do the following:

• Generate payloads.
• For each of them call openURL.
• Check if the app generates a crash report (.ips) in /private/var/mobile/Library/Logs/CrashReporter.

The FuzzDB project offers fuzzing dictionaries that you can use as payloads.

Using Frida

Doing this with Frida is pretty easy, as explained in this blog post to see an example that fuzzes the iGoat-Swift app (working on iOS 11.1.2).

Before running the fuzzer we need the URL schemes as inputs. From the static analysis we know that the iGoat-Swift app supports the following URL scheme and parameters: iGoat://?contactNumber={0}&message={0}.

$ frida -U SpringBoard -l ios-url-scheme-fuzzing.js
[iPhone::SpringBoard]-> fuzz("iGoat", "iGoat://?contactNumber={0}&message={0}")
Watching for crashes from iGoat...
No logs were moved.
Opened URL: iGoat://?contactNumber=0&message=0
OK!
Opened URL: iGoat://?contactNumber=1&message=1
OK!
Opened URL: iGoat://?contactNumber=-1&message=-1
OK!
Opened URL: iGoat://?contactNumber=null&message=null
OK!
Opened URL: iGoat://?contactNumber=nil&message=nil
OK!
Opened URL: iGoat://?contactNumber=99999999999999999999999999999999999
&message=99999999999999999999999999999999999
OK!
Opened URL: iGoat://?contactNumber=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
...
&message=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
...
OK!
Opened URL: iGoat://?contactNumber=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
...
&message=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
...
OK!
Opened URL: iGoat://?contactNumber='&message='
OK!
Opened URL: iGoat://?contactNumber=%20d&message=%20d
OK!
Opened URL: iGoat://?contactNumber=%20n&message=%20n
OK!
Opened URL: iGoat://?contactNumber=%20x&message=%20x
OK!
Opened URL: iGoat://?contactNumber=%20s&message=%20s
OK!

The script will detect if a crash occurred. On this run it did not detect any crashed but for other apps this could be the case. We would be able to inspect the crash reports in /private/var/mobile/Library/Logs/CrashReporter or in /tmp if it was moved by the script.