I'm trying to see how a certain application is talking to a server in SSL. Basically, the process just hangs when it claims to have done some SSL communication. I want to debug the problem by catching the traffic, but I can't really use a sniffer since SSL will probably look like a hexdump.
Is there a good man-in-the-middle tool that I could use as instrumentation? I just need something that will show me the decrypted communication. Hopefully very easy to setup. I could even point the application to any IP address/port available to my machine (eg localhost:8888), so proxies would be fine. Also, I can probably configure the application to accept any certificate.
What do you use to simulate a man-in-the-middle (mitm) SSL attack?
UPDATE: I tried fiddler and can't get it to work. I installed openssl and typed the following command:
openssl s_client -connect smtp.gmail.com:465
Gmail responds with their certificate and a 220 mx.google.com ESMTP .... However, Fiddler does not capture the traffic. I set the WinINET options in fiddler to "Use the same proxy server for all protocols". Can anyone else get this to work (or not work)? I think I need to find a way to have openssl use a proxy.
Fiddler allows you to implement a man in the middle attack against yourself to see what is inside the SSL tunnel.
Fiddler generates a unique root SSL certificate for your computer, and then creates a session certificate signed by the root. When you configure Fiddler to decrypt SSL for you it acts as a proxy between you and the destination, decrypting the traffic using the site's SSL certificate and then re-encrypting it using its own certificate.
Your browser/application will see an untrusted certificate error. You can get around this error by choosing to trust Fiddler's root certificate.
The folks over at .Net Rocks did a great podcast episode on using Fiddler to sniff your traffic.
I haven't use it for this purpose but Fiddler should be able to do what you want.
Fiddler is a Web Debugging Proxy which
logs all HTTP(S) traffic between your
computer and the Internet. Fiddler
allows you to inspect all HTTP(S)
traffic, set breakpoints, and "fiddle"
with incoming or outgoing data.
Fiddler includes a powerful
event-based scripting subsystem, and
can be extended using any .NET
language.
Fiddler is freeware and can debug
traffic from virtually any
application, including Internet
Explorer, Mozilla Firefox, Opera, and
thousands more.
If you are using the amazingly useful Wireshark sniffer, then you can have it decrypt SSL if you are able to provide it the appropriate key files.
Related
I want to capture traffic from a host using HTTP, but I do not see a response coming back. If I close fiddler, my application runs as normal.
I see '-' in the Result section, where it should have been an HTTP response code. If I manually execute the request using Composer, I get a 200 response. Fiddler is able to capture traffic from all other web applications without issue.
I have installed Fiddler certificate. Troubleshooting Mode returns 200. The host does not use HTTPS, but I have enabled Capture HTTPS Connects anyways.
I am using Fiddler v5.0.20182
Some applications performs certificate pinning. Also web applications can perform certificate pinning e.g. via HTTP Public Key Pinning (HPKP). If you have ever used the web application in your browser without Fiddler, the web app public key has been downloaded and cached in the web-browser.
Afterwards the Fiddler root certificate is no longer accepted for that site/app even it it has been installed correctly. You should be able to identify such problematic connections in Fiddler if you only see a CONNECT request but no subsequent requests to the same domain.
To delete the HPKP in your web browser you should use a fresh profile or clear the complete browser cache. Afterwards only use it with activated Fiddler proxy and SSL decryption. As far as I know Fiddler will remove HPKP data from responses so that the web application should also work with Fiddler in between.
I think you should be able to uncheck the options for https, uncheck the boxes which appear checked here? Or you might be able to skip decryption by adding the host in the box below where it says Skip decryption for the following hosts
Trying to investigate private APIs on apps installed on my Android, I've noticed most modern apps use custom client certificate meaning with the trusted root certificate installed on the Android, Charles still cannot monitor the traffic because the server would reject the handshake from Charles. I imagine either I will need a different tool for the traffic monitoring or I will need to direct Charles to use some custom certificate file embedded in the app itself.
You need that certificate file at hand (I don't know if and how you can extract it from application).
You also need to know the passphrase (password) for that certificate. Charles will ask it when you connect to selected host for 1st time.
Then just use latest Charles (tested on version 4.2.1) menu Proxy -> SSL Proxying Settings, tab Client Certificates and add certificate (PKCS#12 key file) for selected host and port.
I've been using Fiddler in C#.
So far I'm able to intercept requests. However, I need to set a proxy. I did so, the proxy is set.
In Proxy Settings Windows' form, I have for HTTP and Secure: 127.0.0.1 for Proxy address to use and for the Port, 8888.
This is the same that is done when I use Fiddler application directly.
However, when I set it through my C# code, instead of using Fiddler, I can't navigate. My pages give me the message:
Your connection is not secure
What more do I need to do? What Fiddler do that I'm missing to correctly set a proxy?
Usually if it cant make a secure connection, you need to trust Fiddler's root certificate on your development PC. If you are using Firefox you will have to do an additional step to trust the certificate inside FF.
My company uses PAC file to restrict any outgoing traffic through proxy server. The problem is, a lot of software does not provide the option to 'use IE setting', so that they cannot be connected to the internet.
I checked this PAC file up and found the right proxy server. But after I tried to use the proxy setting for these IE-unfriendly software, they still cannot get online. I used chrome to capture some packages and found the http header containing some Negotiation data. So I assume this proxy server uses some auto login mechanism like NTLM or kerberos.
But after I downloaded the famous Proxifier and tried to reroute the net traffic for some software, NTLM method did not work. I get the 502 error. Bummer...
Any hero comes to help! Am I thinking in the wrong way? Merci beacoup!
This is not a programming question but, did you try
cntlm (http://cntlm.sourceforge.net/) or
ntlmaps (http://ntlmaps.sourceforge.net/)?
Hope this helps
I can't work out a definitive answer on this, but from searching I find two links which seem to indicate to me that a server (in this case it's MS Exchange as per the links) can have different certificates in place for https than for secure smtp/TLS.
http://technet.microsoft.com/en-GB/library/bb851505(v=exchg.80).aspx
https://www.sslshopper.com/article-how-to-use-ssl-certificates-with-exchange-2007.html
I have an issue which no-one has been able to help with here and this question is a follow on, in that I am coming to the suspicion that my first problem is that my machine trusts the https certificate, but not the one being used for smtp/TLS. But what I'm asking now, is that even possible?
Going through the diagnostic steps here shows me that the certificates in use when I access my mail server's web interface through https are fully trusted. However when I look at the debug of my c# process it is stating a completely different certificate issued by one of our servers to it's self (the server on which exchange is installed).
So... any one know if it's possible that I am thinking along the right lines... is it possible that when I do an https connection I get one certificate and when I use the .net SMTP client I get a completely different certificate (from exactly the same address, but I assume a different port)?
Is it possible that when I do an https connection I get one certificate and when I use the .net SMTP client I get a completely different certificate (from exactly the same address, but I assume a different port)?
Yes, you can have a different certificate for each listening socket on the machine, that is SMTP and HTTPS can use different certificates. On a machine with multiple hostnames you could even have multiple different certificates on a single socket, which get distinguished by the hostname (using SNI).