I'm using ADAL(a 3rd party OAuth2.0 implementation). I'm trying to collect traces of the communication using Charles as a proxy.
What I imagine is happening (not relying on anything):
ADAL requests a certificate from the Authority through Charles
Charles requests a certificate from the Authority and passes it to ADAL.
ADAL wants to open an SSL channel with the Authority but actually opens it with Charles.
Charles opens an SSL channel with the Authority and forwards any requests/responses to ADAL
However, ADAL rejects the Authority's certificate.
Now as far as I know, certificates are passed unencrypted. So if I was correct in describing all the above steps, how does ADAL know that the entity he's talking to isn't infact the Authority he's supposed to be talking with?
ADAL doesn't really look at the authority's certificate - it checks that the channel used to connect to it is trusted. The presence of a proxy can disrupt the SSL channel trust. If I want to connect via SSL to www.domain.com, I expect the certificate used to establish the channel to be in my trusted authorities, to have a subject that contains www.domain.com, to be still within its validity period, and so on. I am not familiar with Charles, but I guess it might look like a DNS redirect attack from ADAL's viewpoint. You can turn off authority validation in the constructor of AuthenticationContext if you need to do a quick test, but I would strongly recommend against doing that in production code.
HTH
V.
Related
I was trying to get myself familiarised with basic concepts of https when I came across its encryption, which in a nutshell functions as follows,
Now I have seen QA engineers in my company use this tool called burp-suite to intercept request.
What I am confused about is even though the data flows through an encrypted channel, how can any interception tool like burp-suite manage to intercept the request.
Just to try it out I tried to intercept facebook request in burp-suite,
Here you can clearly see the test email test#gmail.com I used in the intercepted request.
Why is this data not encrypted according to https standards?
Or if it is then how do burp-suite manage to decrypt it?
Thank you.
Meta: this isn't really a development or programming question or problem, although Burp is sometimes used for research or debugging.
If you LOOK AT THE DOCUMENTATION on Using Burp Proxy
Burp CA certificate - Since Burp breaks TLS connections between your browser and servers, your browser will by default show a warning message if you visit an HTTPS site via Burp Proxy. This is because the browser does not recognize Burp's TLS certificate, and infers that your traffic may be being intercepted by a third-party attacker. To use Burp effectively with TLS connections, you really need to install Burp's Certificate Authority master certificate in your browser, so that it trusts the certificates generated by Burp.
and following the link provided right there
By default, when you browse an HTTPS website via Burp, the Proxy generates a TLS certificate for each host, signed by its own Certificate Authority (CA) certificate. ...
Using its own generated cert (and matching key, although the webpage doesn't talk about that because it isn't visible to people) instead of the cert from the real site allows Burp to 'terminate' the TLS session from the client, decrypting and examining the data, and then forwarding that data over a different TLS session to the real site, and vice versa on the response (unless configured to do something different like modify the data).
... This CA certificate is generated the first time Burp is run, and stored locally. To use Burp Proxy most effectively with HTTPS websites, you will need to install Burp's CA certificate as a trusted root in your browser.
This is followed by a warning about the risks, and a link to instructions to do so.
Having its own CA cert trusted in the browser means that the generated cert is accepted by the browser and everything looks mostly normal to the browser user (or other client).
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
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.
I'd like to run some encrypted connections between some of my own servers. One can use Curl (or some other mechanism) to connect using HTTPS without SSL certificate verification. I'm using PHP, but the language probably isn't significant for this question.
I'm assuming using HTTPS without a SSL certificate is atleast more secure than doing the exact same connection over plain HTTP, since atleast it's encrypted and an evildoer would have to make a much larger effort to intercept en decrypt the information.
As far as I know an SSL certificate only says "this trusted third party says the server you connect to is owned by the guys that claim to own it". If I connect using my own domainname or IP address, I know I'm the owner. What additional value does an SSL certificate provide if I'm the owner of both ends of a connection?
Not verifying the identity of the server you connect to leaves the connection open to potential MITM attacks. SSL/TLS can be used without certificates (with anonymous cipher suites), but they're insecure (and disabled by default); as the TLS RFC says: "Note that this mode is vulnerable to man-in-the-middle attacks and is therefore deprecated."
In addition, the HTTPS specification itself expects there to be an X.509 certificate.
Checking the identity of the remote party is a necessary element for securing your system. It's not very useful to exchange data secretly with a remote party who may not be who they claim they are (even if the secrecy is guaranteed).
This being said, you don't have to go via a commercial CA. You can either use self-signed certificates, which you would have to import individually into each client as trusted certificate, or create your own institutional CA. There are tools to do this, ranging from OpenSSL's CA.pl (see man-page), TinyCA or OpenCA amongst others. Some operating systems also provide their own small CA capabilities.
If I connect using my own domainname or IP address, I know I'm the
owner. What additional value does an SSL certificate provide if I'm
the owner of both ends of a connection?
The certificate assures you that you're indeed connecting to your machine and that the traffic hasn't been intercepted. That's why you need to check that it's a certificate that you recognise.
SSL certificates are more for the piece of mind of your customers or those using your site. In either case, the data is being transmitted over the same connections - it's just a matter of whether or not a third party is certifying you as being safe.
At my last job, we did all of our internal data transfers at my last job via https/ftps but did not have an SSL certificate until very recently. Since the data transfers were internal, it made no difference.