Disabling SSL Certificate Validation in Spring RestTemplate

Question

I am having two Spring based web apps A and B, on two different machines.

I want to make a https call from web app A to web app B, however I am using a self-signed certificate in Machine B. So my HTTPS request fails.

How can I disable https certificate validation when using RestTemplate in Spring ? I want to disable validation because both web app A and B are within the internal network, but data transfer has to happen over HTTPS

Answer 1

What you need to add is a custom HostnameVerifier class bypasses certificate verification and returns true

HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier() {
            public boolean verify(String hostname, SSLSession session) {
                return true;
            }
        });

This needs to be placed appropriately in your code.

Answer 2

@Bean
public RestTemplate restTemplate() 
                throws KeyStoreException, NoSuchAlgorithmException, KeyManagementException {
    TrustStrategy acceptingTrustStrategy = (X509Certificate[] chain, String authType) -> true;

    SSLContext sslContext = org.apache.http.ssl.SSLContexts.custom()
                    .loadTrustMaterial(null, acceptingTrustStrategy)
                    .build();

    SSLConnectionSocketFactory csf = new SSLConnectionSocketFactory(sslContext);

    CloseableHttpClient httpClient = HttpClients.custom()
                    .setSSLSocketFactory(csf)
                    .build();

    HttpComponentsClientHttpRequestFactory requestFactory =
                    new HttpComponentsClientHttpRequestFactory();

    requestFactory.setHttpClient(httpClient);
    RestTemplate restTemplate = new RestTemplate(requestFactory);
    return restTemplate;
 }

Answer 3

Essentially two things you need to do are use a custom TrustStrategy that trusts all certs, and also use NoopHostnameVerifier() to disable hostname verification. Here is the code, with all the relevant imports:

import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import javax.net.ssl.SSLContext;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.TrustStrategy;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

public RestTemplate getRestTemplate() throws KeyStoreException, NoSuchAlgorithmException, KeyManagementException {
    TrustStrategy acceptingTrustStrategy = new TrustStrategy() {
        @Override
        public boolean isTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {
            return true;
        }
    };
    SSLContext sslContext = org.apache.http.ssl.SSLContexts.custom().loadTrustMaterial(null, acceptingTrustStrategy).build();
    SSLConnectionSocketFactory csf = new SSLConnectionSocketFactory(sslContext, new NoopHostnameVerifier());
    CloseableHttpClient httpClient = HttpClients.custom().setSSLSocketFactory(csf).build();
    HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
    requestFactory.setHttpClient(httpClient);
    RestTemplate restTemplate = new RestTemplate(requestFactory);
    return restTemplate;
}

Answer 4

Add my response with cookie :

    public static void main(String[] args) {
            MultiValueMap<String, String> params = new LinkedMultiValueMap<>();
            params.add("username", testUser);
            params.add("password", testPass);
NullHostnameVerifier verifier = new NullHostnameVerifier(); 
            MySimpleClientHttpRequestFactory requestFactory = new MySimpleClientHttpRequestFactory(verifier , rememberMeCookie);
            ResponseEntity<String> response = restTemplate.postForEntity(appUrl + "/login", params, String.class);

            HttpHeaders headers = response.getHeaders();
            String cookieResponse = headers.getFirst("Set-Cookie");
            String[] cookieParts = cookieResponse.split(";");
            rememberMeCookie = cookieParts[0];
            cookie.setCookie(rememberMeCookie);

            requestFactory = new  MySimpleClientHttpRequestFactory(verifier,cookie.getCookie());
            restTemplate.setRequestFactory(requestFactory);
    }


    public class MySimpleClientHttpRequestFactory extends SimpleClientHttpRequestFactory {

        private final HostnameVerifier verifier;
        private final String cookie;

        public MySimpleClientHttpRequestFactory(HostnameVerifier verifier ,String cookie) {
            this.verifier = verifier;
            this.cookie = cookie;
        }

        @Override
        protected void prepareConnection(HttpURLConnection connection, String httpMethod) throws IOException {
            if (connection instanceof HttpsURLConnection) {
                ((HttpsURLConnection) connection).setHostnameVerifier(verifier);
                ((HttpsURLConnection) connection).setSSLSocketFactory(trustSelfSignedSSL().getSocketFactory());
                ((HttpsURLConnection) connection).setAllowUserInteraction(true);
                String rememberMeCookie = cookie == null ? "" : cookie; 
                ((HttpsURLConnection) connection).setRequestProperty("Cookie", rememberMeCookie);
            }
            super.prepareConnection(connection, httpMethod);
        }

        public SSLContext trustSelfSignedSSL() {
            try {
                SSLContext ctx = SSLContext.getInstance("TLS");
                X509TrustManager tm = new X509TrustManager() {

                    public void checkClientTrusted(X509Certificate[] xcs, String string) throws CertificateException {
                    }

                    public void checkServerTrusted(X509Certificate[] xcs, String string) throws CertificateException {
                    }

                    public X509Certificate[] getAcceptedIssuers() {
                        return null;
                    }
                };
                ctx.init(null, new TrustManager[] { tm }, null);
                SSLContext.setDefault(ctx);
                return ctx;
            } catch (Exception ex) {
                ex.printStackTrace();
            }
            return null;
        }

    }


    public class NullHostnameVerifier implements HostnameVerifier {
           public boolean verify(String hostname, SSLSession session) {
              return true;
           }
        }

Answer 5

You can use this with HTTPClient API.

public RestTemplate getRestTemplateBypassingHostNameVerifcation() {
    CloseableHttpClient httpClient = HttpClients.custom().setSSLHostnameVerifier(new NoopHostnameVerifier()).build();
    HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
    requestFactory.setHttpClient(httpClient);
    return new RestTemplate(requestFactory);

}

Answer 6

I found a simple way

    TrustStrategy acceptingTrustStrategy = (X509Certificate[] chain, String authType) -> true;
    SSLContext sslContext = org.apache.http.ssl.SSLContexts.custom().loadTrustMaterial(null, acceptingTrustStrategy).build();
    SSLConnectionSocketFactory csf = new SSLConnectionSocketFactory(sslContext);
    CloseableHttpClient httpClient = HttpClients.custom().setSSLSocketFactory(csf).build();
    HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
    requestFactory.setHttpClient(httpClient);

    RestTemplate restTemplate = new RestTemplate(requestFactory);

Answer 7

To overrule the default strategy you can create a simple method in the class where you are wired your restTemplate:

 protected void acceptEveryCertificate() throws KeyStoreException, NoSuchAlgorithmException, KeyManagementException {

    TrustStrategy acceptingTrustStrategy = new TrustStrategy() {
        @Override
        public boolean isTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {
            return true;
        }
    };

    restTemplate.setRequestFactory(new HttpComponentsClientHttpRequestFactory(
            HttpClientBuilder
                    .create()
                    .setSSLContext(SSLContexts.custom().loadTrustMaterial(null, acceptingTrustStrategy).build())
                    .build()));
}

Note: Surely you need to handle exceptions since this method only throws them further!