Writing Handlers
Firesheep works by sniffing http requests that include the cookie values for specific websites. In order to create new handler you first need to discover which cookie is used by the website to identify you.
Discovering which cookie is required
Download a plugin that will allow you to edit and delta cookies from your browser. (FireCookie for firefox is good or "Edit This Cookie for Chrome" is good) Go to webpage you want to hijack. Remove one cookie at a time then refresh the page to see if you are still logged in. If you delete the session cookie it will look like you're logged out. add the cookie back and try a different cookie. Repeat for all cookies. Sometimes you'll need multiple cookies to identify yourself to the website, so take a note of each cookie that logs you out.
Create your handler
Find your handlers directory (TODO add paths for OSX and Windows)
Create a file in the handlers directory named website.js (replace website with the url you're using)
Add the following code to the js file you just created.
register({
name: 'website.com', //the name that will show up in the Firesheep sidebar
url: 'http://www.website.com/', //the website url that Firesheep will match on
icon: 'http://website.com/images/favicon.gif?2', //a full path to a favicon if the favicon isn't in the default location (optional)
domains: [ 'website.com' ], //the actual domain that Firesheep will look for in the request
sessionCookieNames: [ 'cookie1', 'cookie2' ], //a list of cookie key names that firesheep will intercept and send on
//your behalf (this should be the list of cookies you noted in the previous step)
identifyUser: function() { //Firesheep can make a request to discover some information about the cookie (username and avatar) for the buddy list
var site = this.httpGet(this.siteUrl); //this will pull down a page that contains the value for the username and avatar
this.userName = site.body.querySelector('input#user_email.text_field').value; //use a query selector to pull out the username from the page (optional)
this.userAvatar = resp.body.querySelector('#navAccountPic img').src; //another query selector to grab the image (optional)
}
});
That's about it. Restart Firefox to make sure Firesheep picks up your new handler. Then as you tweak your handler simply stop and restart Firesheep from intercepting and it'll pick up your changes.
