WebView: how to avoid security alert from Google Play upon implementation of onReceivedSslError

user_1183691 0
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I have a link which will open in WebView. The problem is it cannot be open until I override onReceivedSslError like this:

@Override
public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
    handler.proceed();
}

I am getting security alert from Google Play saying:

Security alert Your application has an unsafe implementation of the WebViewClient.onReceivedSslError handler. Specifically, the implementation ignores all SSL certificate validation errors, making your app vulnerable to man-in-the-middle attacks. An attacker could change the affected WebView's content, read transmitted data (such as login credentials), and execute code inside the app using JavaScript.

To properly handle SSL certificate validation, change your code to invoke SslErrorHandler.proceed() whenever the certificate presented by the server meets your expectations, and invoke SslErrorHandler.cancel() otherwise. An email alert containing the affected app(s) and class(es) has been sent to your developer account address.

Please address this vulnerability as soon as possible and increment the version number of the upgraded APK. For more information about the SSL error handler, please see our documentation in the Developer Help Center. For other technical questions, you can post to https://www.stackoverflow.com/questions and use the tags “android-security” and “SslErrorHandler.” If you are using a 3rd party library that’s responsible for this, please notify the 3rd party and work with them to address the issue.

To confirm that you've upgraded correctly, upload the updated version to the Developer Console and check back after five hours. If the app hasn't been correctly upgraded, we will display a warning.

Please note, while these specific issues may not affect every app that uses WebView SSL, it's best to stay up to date on all security patches. Apps with vulnerabilities that expose users to risk of compromise may be considered dangerous products in violation of the Content Policy and section 4.4 of the Developer Distribution Agreement.

Please ensure all apps published are compliant with the Developer Distribution Agreement and Content Policy. If you have questions or concerns, please contact our support team through the Google Play Developer Help Center.

If I remove onReceivedSslError (handler.proceed()), then page won't open.

Is there any way I can open the page in WebView and avoid security alert?

sslerrorhandler android-security android-webview google-play android
8 Answers

I needed to check our truststore before show any message to the user so I did this:

public class MyWebViewClient extends WebViewClient {
private static final String TAG = MyWebViewClient.class.getCanonicalName();

Resources resources;
Context context;

public MyWebViewClient(Resources resources, Context context){
    this.resources = resources;
    this.context = context;
}

@Override
public void onReceivedSslError(WebView v, final SslErrorHandler handler, SslError er){
    // first check certificate with our truststore
    // if not trusted, show dialog to user
    // if trusted, proceed
    try {
        TrustManagerFactory tmf = TrustManagerUtil.getTrustManagerFactory(resources);

        for(TrustManager t: tmf.getTrustManagers()){
            if (t instanceof X509TrustManager) {

                X509TrustManager trustManager = (X509TrustManager) t;

                Bundle bundle = SslCertificate.saveState(er.getCertificate());
                X509Certificate x509Certificate;
                byte[] bytes = bundle.getByteArray("x509-certificate");
                if (bytes == null) {
                    x509Certificate = null;
                } else {
                    CertificateFactory certFactory = CertificateFactory.getInstance("X.509");
                    Certificate cert = certFactory.generateCertificate(new ByteArrayInputStream(bytes));
                    x509Certificate = (X509Certificate) cert;
                }
                X509Certificate[] x509Certificates = new X509Certificate[1];
                x509Certificates[0] = x509Certificate;

                trustManager.checkServerTrusted(x509Certificates, "ECDH_RSA");
            }
        }
        Log.d(TAG, "Certificate from " + er.getUrl() + " is trusted.");
        handler.proceed();
    }catch(Exception e){
        Log.d(TAG, "Failed to access " + er.getUrl() + ". Error: " + er.getPrimaryError());
        final AlertDialog.Builder builder = new AlertDialog.Builder(context);
        String message = "SSL Certificate error.";
        switch (er.getPrimaryError()) {
            case SslError.SSL_UNTRUSTED:
                message = "O certificado não é confiável.";
                break;
            case SslError.SSL_EXPIRED:
                message = "O certificado expirou.";
                break;
            case SslError.SSL_IDMISMATCH:
                message = "Hostname inválido para o certificado.";
                break;
            case SslError.SSL_NOTYETVALID:
                message = "O certificado é inválido.";
                break;
        }
        message += " Deseja continuar mesmo assim?";

        builder.setTitle("Erro");
        builder.setMessage(message);
        builder.setPositiveButton("Sim", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                handler.proceed();
            }
        });
        builder.setNegativeButton("Não", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                handler.cancel();
            }
        });
        final AlertDialog dialog = builder.create();
        dialog.show();
    }
}
}
user_83660590

I had the same issue and tried all the above-mentioned suggestions as below.

  1. Implement onReceivedSslError() by giving the chance to the user to decide handler.proceed(); or handler.cancel(); when a SSL error occurred
  2. Implement onReceivedSslError() to call handler.cancel(); whenever a SSL issue occurred without considering user's decision.
  3. Implement onReceivedSslError() to verify SSL certificate locally addition to checking error.getPrimaryError() and providing the user to decide handler.proceed(); or handler.cancel(); only if the SSL certificate is valid. If not just call handler.cancel();
  4. Removing the implementation of onReceivedSslError() and just let to happen Android default behavior.

Even after trying all the above attempts, Google Play was keeping sending the same notification mail mentioning the same error and the old APK version (Even though in the all above attempts we changed both version code and version name in the Gradle)

We were in huge trouble and contacted Google Support via mail and asked

"We are uploading the higher versions of the APK but the review result says the same error mentioning the old buggy APK version. What's the reason for that ?"

After a few days, google support replied to our request as follows.

Please note that you must completely replace version 12 in your Production track. It means that you'll have to full rollout a higher version in order to deactivate version 12.

The highlighted point was never found or mentioned in the play console or any forum.

According to that guideline in the classic Google play view, we checked the production track and there were both buggy versions and the latest bug fixed version but the bug fix version's rollout percentage is 20%. So, turned it to full rollout then the buggy version disappeared from the production track. After more than 24 hour review time version has come back.

NOTE: When we had this issue Google has just moved to a new UI version of their play console and it had missed some views in the previous UI version or classic view. Since we were using the latest view we couldn't notice what was happening. Simply what happened was Google reviewed the same previous buggy version of the APK since the new one was not full roll-out.

user_55493010

In my situation:This error occured when we try to updated apk uploaded into the Google Play store,and getting SSL Error: Then i have used following code

private class MyWebViewClient extends WebViewClient {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            try {
                progressDialog.dismiss();
            } catch (WindowManager.BadTokenException e) {
                e.printStackTrace();
            }
            super.onPageFinished(view, url);
        }

        @Override
        public void onReceivedSslError(WebView view, final SslErrorHandler handler, SslError error) {

 final AlertDialog.Builder builder = new AlertDialog.Builder(PayNPayWebActivity.this);
            builder.setMessage(R.string.notification_error_ssl_cert_invalid);
            builder.setPositiveButton("continue", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    handler.proceed();
                }
            });
            builder.setNegativeButton("cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    handler.cancel();
                }
            });
            final AlertDialog dialog = builder.create();
            dialog.show();
        }
    }
user_56455410
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