How to capture the SAML response of a request in which hidden SAML POST is present? - authentication

Question

I would like to capture the SAML Response from a URL request made which uses hidden SAML authentication. I am able to see the response in Fiddler but how to save it for further analysis. Post the redirect request by the URL, SAML reponse with "200 OK" arrives in fiddler and I want to capture it. Is there any Powershell utility which can be used to do the same or Do I have to automate the Fiddler itself using some module. Please suggest if any other option is also there.
I have tried some snippets with "Invoke-WebRequest" in Powershell but not able to reproduce much regarding the SAML Response.

Answer 1

Tooting my own horn but my chrome plugin will help you with this. It adds a ta to the dev tools console. Then tabs show all traffic and highlights the ones wiyh saml messages. When you click one it will show you the saml xml in clear text nicely formated.

Answer 2

I have tried a lot of things and finally getting it almost done with the help of phantomjs.
var page = require('webpage').create();
page.customHeaders={'Authorization': 'Basic '+btoa('USER:PASSWORD')};
// hook into initial request
page.onResourceRequested = function(request) {
//console.log("Request: "+ JSON.stringify(request, undefined, 4));
var req_json = JSON.stringify(request, undefined, 4);
if (request.method == "POST" && request.postData != null){
//console.log("Request: "+ JSON.stringify(request, undefined, 4));
console.log("SAML Req/Resp: \n" + request.postData);
}
};
// hook to response
page.onResourceReceived = function(response) {
//console.log("Response: "+ JSON.stringify(response, undefined, 4));
var resp_json = JSON.stringify(response, undefined, 4);
};
page.open("https://yourURLwithhiddenSAML");
For now I am able to get the postdata with SAMLRequest and SAMLResponse and redirecting the output to some file. However, there is one more thing I have noticed. If I add
phantom.exit();
inside the function I am not able to get the complete request/response lifecycle which contains SAML.