Cryoprison

A mobile app jailbreak detector to be used in Xamarin.

Supports iOS and Android.

Overview

The host application should instantiate a JailbreakDetector from the correct Cryoprison platform library. It is recommended that debug builds be configured to be simulator-friendly.

Initialization

    if (Cryoprison.Factory.IsSupported)
    {
        var env = Cryoprison.Factory.CreateEnvironment();

        env.Reporter.OnJailbreakReported = (id) =>
        {
			// Global hook for jailbreak reporting, e.g. to
			// forward the issue to analytics
            Console.WriteLine($"Jailbreak: {id ?? "<null>"}");
        };

        env.Reporter.OnExceptionReported = (message, exception) =>
        {
			// Global hook for exception occurrance in the
			// cryoprison, e.g. to forward the exception to
			// analytics
            Console.WriteLine($"Jailbreak Error: {message}");
            Console.WriteLine(exception.ToString());
        };

		bool? simulatorFriendly = null;
#if DEBUG
		simulatorFriendly = true;
#endif
        this.jailbreakDetector = Cryoprison.Factory.CreateJailbreakDetector(env, simulatorFriendly);

		// it is recommended that the app query the library to determine
		// if it is jailbroken, e.g.
        var isJailbroken = this.jailbreakDetector.IsJailbroken;
        
		// the app can query to determine what jailbreaks were detected using
		// the violations list. This may indicate what tool was detected, but
		// many tools use similar methodologies so this cannot be gauranteed.
		// e.g.
        var violations = this.jailbreakDetector.Violations;
    }

Usage

The JailbreakDetector implements the IJailbreakDetector interface, which provides three methods, as described below:

Method	Description
IsJailbroken	Runs the jailbreak detection code if neccessary, and returns true if any jailbreaks are detected.
Violations	Runs the jailbreak detection code if neccessary, and returns a list of all jailbreaks that are detected.
Reset	Resets the violations list, causing the next call to IsJailbroken or Violations to re-run the detection code.

Jailbreaks are detected by running Inspectors, which derive from the IInspector interface. When possible, Inspectors are implemented in a platform independent fashion in the Cryoprison.Inspectors namespace. Some Inspectors are however platform dependent and are implemented in the PlatformSpecific namespaces of their OS specific Cryoprison.

Inspectors perform checks, which are configured on a per-platform basis in the platform-specific JailbreakDetector implementations using the Checks class.

The following checks are currently supported:

Method	Platform	Description
DirectoryNotPresent	*	Checks that the configured directory is not present.
FileNotAccessible	*	Checks that the configured file is not readable.
FileNotDestructivelyWritable	*	Checks that the configured file can not be created by the app. Destroys any previous version of the file as a side effect.
FileNotPresent	*	Checks that the configured file is not present.
PathNotSymbolicLink	*	Checks that the configured path is not as symbolic link.
UrlNotOpenable	*	Checks that the configured url can not be opened.
ShouldBeMobileProvisioned	iOS	Checks that the app has a mobile provisioning profile.
ShouldNotBeAbleToLocateFile	Android	Checks that a specific file is not found via 'which'.
ShouldNotHavePackageInstalled	Android	Check that a specific package is not installed.
ShouldNotHavePropValues	Android	Check for specific prop values via 'getprop'
ShouldNotHaveSpecificBuildTags	Android	Check that the kernal was not built with specific build tags, indicating a third party build.

The host may optionally register with the Reporter for global exception handling and jailbreak detection, for example for logging purposes. This is done indirectly via assigning callback methods to the static callbacks found in the JailbreakDetector class:

Method	Description
OnJailbreakReported	Invoked each time a jailbreak is detected, with the ID of the jailbreak.
OnExceptionReported	Invoked each time an exception occurs, with an internal reason and the exception body

NugetTest

The nuget test app is a very simple Xamarin forms application that performs a jailbreak detection check when the main window appears. It references the Cryoprison library as a nuget package.

Library

The Cryoprison library resides in this folder, and can be included via manual means in your project.

Cryoprison

The Cryoprison nuget package resides in this folder.

SampleApp

The sample app is a very simple Xamarin forms application that performs a jailbreak detection check when the main window appears. It references the Cryoprison library directly as an assembly.

Current state of this project

Please note that this project is not currently maintained, nor is it's Nuget package.

If the project were maintained properly, then the Nuget package would be the recommended way to use it, but since it's not, the library is the way to go.