Authentication Bad Practice: Missing Host Check

The authentication handling callback for NSURLConnection or NSURLSession fails to check what host it is sending the credentials to.

The application implements the NSURLConnection or NSURLSession callbacks to handle authentication requests. Forgetting to ensure that the authentication request comes from the expected host would result in credentials being sent to every URL the application loads. In addition, failing to check that the credentials can be sent securely would result in credentials being stolen.

Example 1: The following application sends user credentials to any host asking for authentication:

- (void)URLSession:(NSURLSession *)session didReceiveChallenge:(NS URLAuthenticationChallenge *)challenge completionHandler:(void (^)(NS URLSessionAuthChallengeDisposition, NSURLCredential *))completionHandler { 
    NSString *user = [self getUser]; 
    NSString *pass = [self getPassword]; 

    NSURLCredential *cred = [NSURLCredential credentialWithUser:user 
    password:pass persistence:NSURLCredentialPersistenceForSession]; 
    completionHandler(NSURLSessionAuthChallengeUseCredential, credential);
}