I am working on a login page using spring security. The page need to provide an option for user to use their certificate instead of username and password. However I am stuck in following scenarios :
Say you have a certificate signed by XYZ company installed in your browser. Now server (trusted XYZ) wanted to validate the certificate... but questions are :
Q1. How can server 'request' browser to provide "the right certificate" (assuming you have more than one certificate installed in your browser)?
Q2. Is it possible to have a button on the login page for user to send his certificate only when he click on the button?
Q3. Say the server received your certificate, can the server say "yes, you have proof who you said you are" simply by looking into the certificate chain (signed by XYZ company)?
Thanks,
From a security newbie :)
This is possible. All you'd have to do would be to setup an ssl site with client certificates required. Browsers support this out of the box, most present an internal cert store, ie shows a user cert store from the os. You should consult your server framework docs on how to turn on the client cert requirement on the ssl connection.
As for q2, you could have two websites, your app and your auth provider. The app shows the button and this redirects to your auth provider which requires the client certificate. Then, the auth provider uses any sso protocol (oauth2, saml) to return the user identity to the application.
As for cert validation, you could either validate the chain or have a mapping between usernames and cert thumbprints at the server side.
Related
I have installed a SSL certificate (comodo PositiveSSL) for my domain and forced NGINX to only use HTTPS.
I run the test on SSL analyzer
https://sslanalyzer.comodoca.com/?url=domain.com
Validation Type Domain Validated (DV)
Trusted by Microsoft? Yes
Trusted by Mozilla? Yes
We have our mobile app for Android and IOS getting some data from our https://example.com/api webservices.
So i have installed Packet Capture mobile app on my android to verify whether the data transferred between the webservice api and our mobile app is secured.
First i tried with enabling the following in Packet capture mobile app :-
I have contacted comodo ssl support, they said
that the certificate is installed well and its working fine. There is
nothing wrong with the certificate and installation process and the
web-site https://example.com/ is also completely secured with Green Pad
lock on it.
I run the same test on instagram app, when open instagram , showing network error. Like instagram discovering by some way that i am trying to capture a network packets so their app network will be disabled.
I want to do the same way of what instagram did .
Please Advice.
Don't worry, if your certificate is valid and contains the right domain name then you've already done everything needed.
A "man in the middle attack" is an attack done on the client.
The client think the attacker is the website by compromising his DNS
Then the attacker relay in and out traffic from/to the real server.
The server is secure but not the client.
Like RamKumar said the client need to trust the attacker certificate like you did
EDIT:
You can also use TLS with mutual authentication (mTLS).
With this protocol the client AND the server exchange certificate public keys.
It work as follow:
A client requests access to a protected resource.
The server presents its certificate to the client.
The client verifies the server’s certificate.
If successful, the client sends its certificate to the server.
The server verifies the client’s credentials.
If successful, the server grants access to the protected resource requested by the client.
Some sample:
https://www.nccgroup.trust/us/about-us/newsroom-and-events/blog/2011/october/mutual-authentication-in-android-and-ios/
With this protocol the man in the middle attack is still possible but the attacker's certificates need to be trusted by both client and server
Another custom approach would be to add another layer of encryption using asymetric cipher.
To remove that possibility you can use Certificate Pinning to make sure that only the specific Certificate you use can be used to prevent the device from using any other Certificate, even if it was signed from a trusted CA. This may still be circumvented by a user, but now he has to modify the application itself in order to disable the check, or change the pinned certificate
Have a look at how Certificate Authority (CA) works. In your case, what happens is that the Packet capture mobile app installs it's own CA. Now Packet capture becomes a trusted CA for your device and certificates signed by them are accepted. Then this app creates its own certificate saying example.com and signs it.
So when it performs man in the middle attack, the client (your app) communicates with Packet capture and not example.com, but your app believes it's communicating with the example.com, since the certificate provided by Packet capture is signed by a trusted CA (Packet capture CA itself).
Hence this works only when your install their CA. However a secured connection is made between Packet capture and example.com
I am trying to wrap my head around certificates and any help is appreciated. So far this is what I understand, please correct me if I am wrong.
When using the browser when I navigate to the https site the browser downloads the certificate(without the private key) and then continues to send the data over https?
I have come across some sites (especially when developing) that require you to install the certificate on the local machine before making a service call. What is the purpose here and how does it work?
I have also seen some scenarios where you need to install the certificate on the client machine for authentication purposes for example if you are using an email client, how does this work?
When using the browser when I navigate to the https site the browser downloads the certificate(without the private key) and then continues to send the data over https?
No, the browser and the server stablish a SSL/TLS secure channel with a symmetric encryption key. During the handshake process the server presents the https certificate and digitally signs some data with the private key as a proof of authenticity.
I have come across some sites (especially when developing) that require you to install the certificate on the local machine before making a service call. What is the purpose here and how does it work?
The client must trust the server certificate. Usually it has a list with the Certification Authorities for which certificates are accepted. For other certificates is needed to add them to the trust list. If not, the communication will be rejected
I have also seen some scenarios where you need to install the certificate on the client machine for authentication purposes for example if you are using an email client, how does this work?
Probably the same case as the previous one. Also the public part of the certificate of a user can be used to encrypt a message for him
Does a web browser send client certificates to the web server on demand (means the web server is configured for client authentication and demands the client certificate) or does it just send all of the certificates that it has? If web browser sends client certificate on demand, then how does the web browser know which client certificate to sent to that particular web server?
I put my question on https://security.stackexchange.com/ and got this answer from #gowenfawr:
During the SSL handshake,
If the server requires a digital certificate for client authentication,
the server sends a "client certificate request" that includes a list of
the types of certificates supported and the Distinguished Names of
acceptable Certification Authorities (CAs).
(quote is from a reasonably lucid explanation of the SSL handshake by
IBM.)
The client then compares the certificates in its store against that
list to see if it has any signed by the CAs that the server listed. If
it finds one, it will send it, usually after prompting the user
whether they want to send it. Presumably if there were multiple
matches it would ask the user which to send (if any).
Linked to my question about client certificate authentication done the right way I was wondering whether I have to take the step to link a certificate to a user (active directory or local user) in order to have clientcertificate authentication to work as expected?
And is it necessary to disable all other authentication schemes (anonymous, windows) for clientcerticate authentication to happen?
See this question on the IIS forum:
This is what I would like to achieve:
A SSL-certificate for the URL itself (https://example.company.com). To my understanding this certificate does not have any connection whatsoever to client certificates.
Client certificates issued from my local CA and shared to trusted clients.
Some way of specifying which client certificates are allowed to connect to a specific IIS web site.
3 seems... complicated, to say the least. If I just set everything up and connect with a client certificate I have issued it works. The CA and the web server are on the same domain (if that matters), and I have added the root certificate from the CA to the trusted CAs on the web server. However, at this stage I have not told the web server which client certificates to accept, so my first guess was that it accepts all client certificates [chained to] any CA it trusts.
See also this question, which links to this site, which is dead.
It comes down to creating a "Certificate Trust List", or to mapping certificates to user accounts.
You can however implement a custom certificate validator in your service, how to do so is explained here.
I am somewhat confused as to how two-way SSL works. How does the client create its certificate to send to the server? Is it generated from the server and distributed to the client?
Also, what is the advantage of two-way SSL over one-way SSL?
Both certificates should exist prior to the connection. They're usually created by Certification Authorities (not necessarily the same). (There are alternative cases where verification can be done differently, but some verification will need to be made.)
The server certificate should be created by a CA that the client trusts (and following the naming conventions defined in RFC 6125).
The client certificate should be created by a CA that the server trusts.
It's up to each party to choose what it trusts.
There are online CA tools that will allow you to apply for a certificate within your browser and get it installed there once the CA has issued it. They need not be on the server that requests client-certificate authentication.
The certificate distribution and trust management is the role of the Public Key Infrastructure (PKI), implemented via the CAs. The SSL/TLS client and servers and then merely users of that PKI.
When the client connects to a server that requests client-certificate authentication, the server sends a list of CAs it's willing to accept as part of the client-certificate request. The client is then able to send its client certificate, if it wishes to and a suitable one is available.
The main advantages of client-certificate authentication are:
The private information (the private key) is never sent to the server. The client doesn't let its secret out at all during the authentication.
A server that doesn't know a user with that certificate can still authenticate that user, provided it trusts the CA that issued the certificate (and that the certificate is valid). This is very similar to the way passports are used: you may have never met a person showing you a passport, but because you trust the issuing authority, you're able to link the identity to the person.
You may be interested in Advantages of client certificates for client authentication? (on Security.SE).
What you call "Two-Way SSL" is usually called TLS/SSL with client certificate authentication.
In a "normal" TLS connection to example.com only the client verifies that it is indeed communicating with the server for example.com. The server doesn't know who the client is. If the server wants to authenticate the client the usual thing is to use passwords, so a client needs to send a user name and password to the server, but this happens inside the TLS connection as part of an inner protocol (e.g. HTTP) it's not part of the TLS protocol itself. The disadvantage is that you need a separate password for every site because you send the password to the server. So if you use the same password on for example PayPal and MyPonyForum then every time you log into MyPonyForum you send this password to the server of MyPonyForum so the operator of this server could intercept it and try it on PayPal and can issue payments in your name.
Client certificate authentication offers another way to authenticate the client in a TLS connection. In contrast to password login, client certificate authentication is specified as part of the TLS protocol. It works analogous to the way the client authenticates the server: The client generates a public private key pair and submits the public key to a trusted CA for signing. The CA returns a client certificate that can be used to authenticate the client. The client can now use the same certificate to authenticate to different servers (i.e. you could use the same certificate for PayPal and MyPonyForum without risking that it can be abused). The way it works is that after the server has sent its certificate it asks the client to provide a certificate too. Then some public key magic happens (if you want to know the details read RFC 5246) and now the client knows it communicates with the right server, the server knows it communicates with the right client and both have some common key material to encrypt and verify the connection.
In two way ssl the client asks for servers digital certificate and server ask for the same from the client. It is more secured as it is both ways, although its bit slow. Generally we dont follow it as the server doesnt care about the identity of the client, but a client needs to make sure about the integrity of server it is connecting to.