by @_r3ggi

ISS Description

🌏 iOS Security Suite is an advanced and easy-to-use platform security & anti-tampering library written in pure Swift! If you are developing for iOS and you want to protect your app according to the OWASP MASVS standard, chapter v8, then this library could save you a lot of time. 🚀

What ISS detects:

• Jailbreak (even the iOS 11+ with brand new indicators! 🔥)
• Attached debugger 👨🏻‍🚀
• If an app was run in an emulator 👽
• Common reverse engineering tools running on the device 🔭

Setup

There are 4 ways you can start using IOSSecuritySuite

1. Add source

Add IOSSecuritySuite/*.swift files to your project

2. Setup with CocoaPods

pod 'IOSSecuritySuite'

3. Setup with Carthage

github "securing/IOSSecuritySuite"

4. Setup with Swift Package Manager

.package(url: "https://github.com/securing/IOSSecuritySuite.git", from: "1.5.0")

Update Info.plist

After adding ISS to your project, you will also need to update your main Info.plist. There is a check in jailbreak detection module that uses canOpenURL(_:) method and requires specifying URLs that will be queried.

<key>LSApplicationQueriesSchemes</key>
<array>
	<string>cydia</string>
	<string>undecimus</string>
	<string>sileo</string>
	<string>zbra</string>
</array>

How to use

Jailbreak detector module

• The simplest method returns True/False if you just want to know if the device is jailbroken or jailed

if IOSSecuritySuite.amIJailbroken() {
	print("This device is jailbroken")
} else {
	print("This device is not jailbroken")
}

• Verbose, if you also want to know what indicators were identified

let jailbreakStatus = IOSSecuritySuite.amIJailbrokenWithFailMessage()
if jailbreakStatus.jailbroken {
	print("This device is jailbroken")
	print("Because: \(jailbreakStatus.failMessage)")
} else {
	print("This device is not jailbroken")
}

The failMessage is a String containing comma-separated indicators as shown on the example below: Cydia URL scheme detected, Suspicious file exists: /Library/MobileSubstrate/MobileSubstrate.dylib, Fork was able to create a new process

• Verbose & filterable, if you also want to for example identify devices that were jailbroken in the past, but now are jailed

let jailbreakStatus = IOSSecuritySuite.amIJailbrokenWithFailedChecks()
if jailbreakStatus.jailbroken {
   if (jailbreakStatus.failedChecks.contains { $0.check == .existenceOfSuspiciousFiles }) && (jailbreakStatus.failedChecks.contains { $0.check == .suspiciousFilesCanBeOpened }) {
         print("This is real jailbroken device")
   }
}

Debugger detector module

let amIDebugged: Bool = IOSSecuritySuite.amIDebugged()

Deny debugger at all

IOSSecuritySuite.denyDebugger()

Emulator detector module

let runInEmulator: Bool = IOSSecuritySuite.amIRunInEmulator()

Reverse engineering tools detector module

let amIReverseEngineered: Bool = IOSSecuritySuite.amIReverseEngineered()

System proxy detector module

let amIProxied: Bool = IOSSecuritySuite.amIProxied()

Experimental features

Runtime hook detector module

let amIRuntimeHooked: Bool = amIRuntimeHook(dyldWhiteList: dylds, detectionClass: SomeClass.self, selector: #selector(SomeClass.someFunction), isClassMethod: false)

Symbol hook deny module

// If we want to deny symbol hook of Swift function, we have to pass mangled name of that function
denySymbolHook("$s10Foundation5NSLogyySS_s7CVarArg_pdtF")   // denying hooking for the NSLog function
NSLog("Hello Symbol Hook")
     
denySymbolHook("abort") 
abort()

MSHook detector module

// Function declaration
func someFunction(takes: Int) -> Bool {
	return false
} 

// Defining FunctionType : @convention(thin) indicates a “thin” function reference, which uses the Swift calling convention with no special “self” or “context” parameters.
typealias FunctionType = @convention(thin) (Int) -> (Bool)

// Getting pointer address of function we want to verify
func getSwiftFunctionAddr(_ function: @escaping FunctionType) -> UnsafeMutableRawPointer {
	return unsafeBitCast(function, to: UnsafeMutableRawPointer.self)
}

let funcAddr = getSwiftFunctionAddr(someFunction)
let amIMSHooked = IOSSecuritySuite.amIMSHooked(funcAddr)

MSHook deny module

// Function declaration
func denyDebugger(value: Int) {
}

// Defining FunctionType : @convention(thin) indicates a “thin” function reference, which uses the Swift calling convention with no special “self” or “context” parameters.
typealias FunctionType = @convention(thin) (Int)->()

// Getting original function address
let funcDenyDebugger: FunctionType = denyDebugger 
let funcAddr = unsafeBitCast(funcDenyDebugger, to: UnsafeMutableRawPointer.self)


if let originalDenyDebugger = denyMSHook(funcAddr) {
// Call the original function with 1337 as Int argument
     unsafeBitCast(originalDenyDebugger, to: FunctionType.self)(1337)
 } else {
     denyDebugger()
 }

File integrity verifier module

// Determine if application has been tampered with 
if IOSSecuritySuite.amITampered([.bundleID("biz.securing.FrameworkClientApp"),
    .mobileProvision("2976c70b56e9ae1e2c8e8b231bf6b0cff12bbbd0a593f21846d9a004dd181be3"),
    .machO("IOSSecuritySuite", "6d8d460b9a4ee6c0f378e30f137cebaf2ce12bf31a2eef3729c36889158aa7fc")]).result {
    print("I have been Tampered.")
}
else {
    print("I have not been Tampered.")
}

// Manually verify SHA256 hash value of a loaded dylib
if let hashValue = IOSSecuritySuite.getMachOFileHashValue(.custom("IOSSecuritySuite")), hashValue == "6d8d460b9a4ee6c0f378e30f137cebaf2ce12bf31a2eef3729c36889158aa7fc" {
    print("I have not been Tampered.")
}
else {
    print("I have been Tampered.")
}
 
// Check SHA256 hash value of the main executable
// Tip: Your application may retrieve this value from the server
if let hashValue = IOSSecuritySuite.getMachOFileHashValue(.default), hashValue == "your-application-executable-hash-value" {
    print("I have not been Tampered.")
}
else {
    print("I have been Tampered.")
}

Breakpoint detection module

func denyDebugger() {
    // add a breakpoint at here to test
}
     
typealias FunctionType = @convention(thin) ()->()
let func_denyDebugger: FunctionType = denyDebugger   // `: FunctionType` is a must
let func_addr = unsafeBitCast(func_denyDebugger, to: UnsafeMutableRawPointer.self)
let hasBreakpoint = IOSSecuritySuite.hasBreakpointAt(func_addr, functionSize: nil)

if hasBreakpoint {
    print("Breakpoint found in the specified function")
} else {
    print("Breakpoint not found in the specified function")
}

Security considerations

Before using this and other platform security checkers, you have to understand that:

• Including this tool in your project is not the only thing you should do in order to improve your app security! You can read a general mobile security whitepaper here.
• Detecting if a device is jailbroken is done locally on the device. It means that every jailbreak detector may be bypassed (even this)!
• Swift code is considered to be harder to manipulate dynamically than Objective-C. Since this library was written in pure Swift, the IOSSecuritySuite methods shouldn't be exposed to Objective-C runtime (which makes it more difficult to bypass ✅). You have to know that attacker is still able to MSHookFunction/MSFindSymbol Swift symbols and dynamically change Swift code execution flow.
• It's also a good idea to obfuscate the whole project code, including this library. See Swiftshield

Contribution ❤️

Yes, please! If you have a better idea or you just want to improve this project, please text me on Twitter or Linkedin. Pull requests are more than welcome!

Special thanks: 👏🏻

• kubajakowski for pointing out the problem with canOpenURL(_:) method
• olbartek for code review and pull request
• benbahrenburg for various ISS improvements
• fotiDim for adding new file paths to check
• gcharita for adding the Swift Package Manager support
• rynaardb for creating the amIJailbrokenWithFailedChecks() method
• undeaDD for various ISS improvements
• fnxpt for adding HideJB detection
• TannerJin for MSHook, RuntimeHook and SymbolHook modules
• NikoXu for adding file integrity module

TODO

• Research Installer5 and Zebra Package Manager detection ( Cydia Alternatives )

License

See the LICENSE file.

References

While creating this tool I used:

• 🔗 https://github.com/TheSwiftyCoder/JailBreak-Detection
• 🔗 https://github.com/abhinashjain/jailbreakdetection
• 🔗 https://gist.github.com/ddrccw/8412847
• 🔗 https://gist.github.com/bugaevc/4307eaf045e4b4264d8e395b5878a63b
• 📚 "iOS Application Security" by David Thiel