Swift 3 NTLM authentication - authentication

Question

For a recent project I tried to pull some data from a server in the SOAP and oData format respectively, that is protected with a Microsoft NTLM authentication, and it has been a nightmare figuring out how to do it, none of the online examples really worked.

Answer 1

So here is my solution; I had to adapt, expand and combine a few different sources. I hope this helps someone in the future.
You might have to allow arbitrary loads!!
Adapted from:
https://gist.github.com/stevenschobert/f374c999e5cba6ccf09653b846967c83
https://blogs.msdn.microsoft.com/chiranth/2013/09/20/ntlm-want-to-know-how-it-works/
import UIKit
class ViewController: UIViewController {
var username: String? = nil
var password: String? = nil
lazy var conn: URLSession = {
let config = URLSessionConfiguration.ephemeral
let session = URLSession(configuration: config, delegate: self, delegateQueue: nil)
return session
}()
override func viewDidLoad() {
super.viewDidLoad()
username = "<username>"
password = "<password>"
ntlm()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func ntlm() {
let urlString = "<url>"
let url = URL(string: urlString)
let request = NSMutableURLRequest(url: url!, cachePolicy: .reloadIgnoringLocalCacheData, timeoutInterval: 60000)
request.httpMethod = "GET"
let task = conn.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
print(response)
print(error)
print(String(data: data!, encoding: .utf8))
})
task.resume()
}
func doesHaveCredentials() -> Bool {
guard let _ = self.username else { return false }
guard let _ = self.password else { return false }
return true
}
}
extension ViewController: URLSessionDelegate {
func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: #escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
print("got challenge")
guard challenge.previousFailureCount == 0 else {
print("too many failures")
challenge.sender?.cancel(challenge)
completionHandler(.cancelAuthenticationChallenge, nil)
return
}
guard challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodNTLM else {
print("unknown authentication method \(challenge.protectionSpace.authenticationMethod)")
challenge.sender?.cancel(challenge)
completionHandler(.cancelAuthenticationChallenge, nil)
return
}
guard self.doesHaveCredentials() else {
challenge.sender?.cancel(challenge)
completionHandler(.cancelAuthenticationChallenge, nil)
DispatchQueue.main.async {
print("Userdata not set")
};
return
}
let credentials = URLCredential(user: self.username!, password: self.password!, persistence: .forSession)
challenge.sender?.use(credentials, for: challenge)
completionHandler(.useCredential, credentials)
}
}