I'm trying to utilize a REST API on a local web server with a self-signed certificate. At runtime, the application throws the error
AuthenticationException: The remote certificate is invalid according to the validation procedure.
I have tried the fix in this answer: https://stackoverflow.com/a/1386568/8980983 however the error remains. Code is below:
static void Main(string[] args)
{
HttpClient httpClient = new HttpClient();
httpClient.DefaultRequestHeaders.Clear();
ServicePointManager.ServerCertificateValidationCallback = delegate (
object s, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
return true;
};
var loginPage = httpClient.GetAsync("https://<local IP address>/loginpage.html").GetAwaiter().GetResult();
//do stuff with response...
}
Any ideas of what I can do to effectively ignore SSL policy errors?
Figured it out. Turns out the HttpClient class doesn't use the ServicePointManager.ServerCertificateValidationCallback method. Solution was as follows:
static void Main(string[] args)
{
HttpClientHandler httpClientHandler = new HttpClientHandler();
httpClientHandler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => { return true; };
HttpClient httpClient = new HttpClient(httpClientHandler);
httpClient.DefaultRequestHeaders.Clear();
var loginPage = httpClient.GetAsync("https://<local IP address>/loginpage.html").GetAwaiter().GetResult();
}
Related
We are using Restsharp in a .NET 4.8 solution for http requests.
We need to bypass ssl validation for http calls for some time until we fix the cert issue.
RestSharp Version=105.2.3.0 is the version used.
We can see in forums for bypassing the ssl and applied that to our code like below but it complains method definition
Class1
{
private readonly IRestClient _restClient;
public Class1(IRestClient restClient)
{
_restClient = restClient;
}
GetApi()
{
restClient.RemoteCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;
RestRequest request = new RestRequest(url, Method.GET);
IRestResponse response = _restClient.Execute(request);
}
}
There is an alternate solution for this suggested in forums, but it says it will apply to entire application.
If we use the code shown here, will it be applied to only that method or is it going to impact all the http calls?
ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => true;
Thanks
try this:
restClient.Options.RemoteCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;
I added WCF connected service reference in my project and set ServicePointManager.ServerCertificateValidationCallback function. For some reason, this callback function is ignored when i am requesting server. I have to notify user about certificate problems and proceed request if user confirms.
static async Task Main(string[] args)
{
ServicePointManager.ServerCertificateValidationCallback = MyServerCertificateValidationCallback;
var data = new DataSoapClient(DataSoapClient.EndpointConfiguration.DataSoap);
data.Endpoint.Address = new EndpointAddress("https://open.helios.eu/demo/Data.asmx");
(data.Endpoint.Binding as BasicHttpBinding).Security.Mode = BasicHttpSecurityMode.Transport;
var result = (await data.GetInfoAsync("GETREDIRECTINFO", string.Empty)).Body.GetInfoResult;
Console.WriteLine(result);
}
private static bool MyServerCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
// function won't execute
return true;
}
Finally i found a solution for my problem. As Abraham Quian mentioned, callback is not working in .net core so I had to use different approach and use X509CertificateValidator. Here is a code snippet:
static async Task Main(string[] args)
{
var data = new ServiceReference1.Service1Client(Service1Client.EndpointConfiguration.BasicHttpsBinding_IService1);
data.Endpoint.Address = new EndpointAddress("https://localhost:5035/Service1.svc");
(data.Endpoint.Binding as BasicHttpBinding).Security.Mode = BasicHttpSecurityMode.Transport;
data.ClientCredentials.ServiceCertificate.SslCertificateAuthentication = new X509ServiceCertificateAuthentication();
data.ClientCredentials.ServiceCertificate.SslCertificateAuthentication.CertificateValidationMode = X509CertificateValidationMode.Custom;
data.ClientCredentials.ServiceCertificate.SslCertificateAuthentication.CustomCertificateValidator = new Validator();
var result = await data.GetDataAsync(1);
Console.WriteLine(result);
}
And there is validator:
internal class Validator : X509CertificateValidator
{
public override void Validate(X509Certificate2 certificate)
{
X509Chain chain = new X509Chain();
if (!chain.Build(certificate))
{
Console.WriteLine($"{chain.ChainStatus.FirstOrDefault().StatusInformation}. Press y to proceed...");
if(Console.ReadKey().KeyChar != 'y')
throw new SecurityTokenValidationException("Service certification is not valid.");
}
}
}
ServicePointManager.ServerCertificateValidationCallback += delegate
{
return true;
};
This code snippet is valid in the Dotnetframework project, it is invalid in the Dotnet Core project.
Generally, in the case of ensuring that the certificate can be trusted, we should install the certificate provided by the server to the Root CA certificate store on the client-side.
In addition, the following code snippet applies to both the DotNet Core project and the Dotnetframework project.
ServiceReference1.TestServiceClient client = new ServiceReference1.TestServiceClient();
client.ClientCredentials.ServiceCertificate.SslCertificateAuthentication = new System.ServiceModel.Security.X509ServiceCertificateAuthentication
{
CertificateValidationMode = System.ServiceModel.Security.X509CertificateValidationMode.None,
RevocationMode = System.Security.Cryptography.X509Certificates.X509RevocationMode.NoCheck
};
Feel free to let me know if the problem still exists.
I am trying to consume Client's Web Service from Web API, Below is the code we are currently using to bypass SSL certificate
ServicePointManager.ServerCertificateValidationCallback += (sender, cert, chain, sslPolicyErrors) => true;
It was working fine, until they disabled TLS 1.0 and TLS 1.1 from their end. Now we have added follwing code to use TLS 1.2 for client server connection
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
ServicePointManager.ServerCertificateValidationCallback += (sender, cert, chain, sslPolicyErrors) => true;
Now i am getting "The request was aborted: Could not create SSL/TLS secure channel." Error only when i am hitting the API for first time, and then getting results if i am continuously hitting the API, If i wait for some time like a minute or so, Again getting same error for first time only.
Setting the security protocol type needs to be done before the issuing request is created. So this:
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
Should appear before this:
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
So if you're seeing it work on subsequent requests, it might be that you're setting the protocol too late.
The following code can be used to help troubleshoot the issue.
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
ServicePointManager.ServerCertificateValidationCallback += ValidateServerCertificate;
...
private static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
// If the certificate is a valid, signed certificate, return true to short circuit any add'l processing.
if (sslPolicyErrors == SslPolicyErrors.None)
{
return true;
}
else
{
// cast cert as v2 in order to expose thumbprint prop - if needed
var requestCertificate = (X509Certificate2)certificate;
// init string builder for creating a long log entry
var logEntry = new StringBuilder();
// capture initial info for the log entry
logEntry.AppendFormat("SSL Policy Error(s): {0} - Cert Issuer: {1} - SubjectName: {2}",
sslPolicyErrors.ToString(),
requestCertificate.Issuer,
requestCertificate.SubjectName.Name);
// check for other error types as needed
if (sslPolicyErrors == SslPolicyErrors.RemoteCertificateChainErrors) //Root CA problem
{
// check chain status and log
if (chain != null && chain.ChainStatus != null)
{
// check errors in chain and add to log entry
foreach (var chainStatus in chain.ChainStatus)
{
logEntry.AppendFormat("|Chain Status: {0} - {1}", chainStatus.Status.ToString(), chainStatus.StatusInformation.Trim());
}
}
}
// replace with your logger
MyLogger.Info(logEntry.ToString().Trim());
}
return false;
}
For those running .NET version 4, they can use below
ServicePointManager.SecurityProtocol = CType(768, SecurityProtocolType) Or CType(3072,SecurityProtocolType)
ServicePointManager.Expect100Continue = True
How can you verify validity of an HTTPS/SSL certificate in .NET?
Ideally I want to establish an HTTPS connection to a website and then find out if that was done in a valid way (certificate not expired, host name matches, certificate chain trusted etc), but the built in HTTP Client seems to ignore certificate errors (and I'm not sure that physically downloading a web page is necessary to verify a certificate?).
I've tried to use the code below (adapted from an answer in the comments) but the ValidationCallback never gets called:
static void Main(string[] args)
{
String url = "https://www.example.com";
HttpWebRequest request = WebRequest.CreateHttp(url);
request.GetResponse();
request.ServerCertificateValidationCallback += ServerCertificateValidationCallback;
Console.WriteLine("End");
Console.ReadKey();
}
private static bool ServerCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
if (sslPolicyErrors == SslPolicyErrors.None)
{
Console.WriteLine("Certificate OK");
return true;
}
else
{
Console.WriteLine("Certificate ERROR");
return false;
}
}
It doesn't get called because you're setting the ValidationCallback after you've already made the request.
Change it to this:
HttpWebRequest request = WebRequest.CreateHttp( url );
request.ServerCertificateValidationCallback += ServerCertificateValidationCallback;
using( HttpWebResponse response = (HttpWebResponse)request.GetResponse() ) { }
Console.WriteLine("End");
...and it will work.
I have seen code samples of how to use WebRequestHandler with HttpClient to embed a certificate in my http request (see snippet below). However, I just tested this with a self-signed cert and it is not working. According to this post this method will not work without a trusted certificate.
I can see the certificate on the server if I send it through the browser or Postman, but not programmatically.
Can someone confirm or deny if HttpClient or WebRequestHandlerperform any kind of certificate validation before sending it as part of the request?
A quick de-compile did not show anything obvious, but there are many things in play along the request pipeline.
Sample code:
var cert = new X509Certificate2(rawCert);
//This call fails, cannot check revocation authority.
//Specific error: The revocation function was unable to check
//revocation for the certificate.
//X509CertificateValidator.ChainTrust.Validate(cert);
var certHandler = new WebRequestHandler()
{
ClientCertificateOptions = ClientCertificateOption.Manual,
UseDefaultCredentials = false
};
certHandler.ClientCertificates.Add(cert);
var Certificateclient = new HttpClient(certHandler)
{
BaseAddress = new Uri("https://web.local")
};
var response = await Certificateclient.GetAsync("somepath");
To use a self signed cert, you can add using System.Net.Security;
add a handler callback method
public static bool ValidateServerCertificate(Object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
return true;
}
and set before invoke the API:
ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(ValidateServerCertificate);
See:
https://es.stackoverflow.com/a/153207/86150
https://social.msdn.microsoft.com/Forums/es-ES/130308da-4092-4f21-8355-ee3c77a22f97/llamar-web-service-con-certificado?forum=netfxwebes