Original URL: http://www.theregister.co.uk/2010/11/09/firesheep_mitigation_analysis/

Firesheep developer poohpoohs mitigation tools

Woolly thinking on cookie-jacker-slapping

By John Leyden

Posted in Security, 9th November 2010 12:34 GMT

The developer of the Firesheep cookie-jacking plug-in has dismissed supposed easy-fix countermeasures as worse than useless.

Eric Butler released the Firefox extension last month in order to illustrate the risk posed by the failure of many sites to encrypt session cookies used to authenticate their users, even if they might run them through a secure server for the initial logon.

As a result, Firesheep can capture login credentials for sites such as Facebook and Twitter from open Wi-Fi networks. These captured cookies would then allow someone to log into a site and impersonate a user.

The basic problem has been well understood in security circles for months, but only reached a wider audience thanks to Firesheep, which makes the whole process of capturing credentials and logging into web services as an imposter as simple as waiting for someone on an open network to log into a vulnerable website before double-clicking on their profile picture.

Butler released the tool in order to highlight the need for vulnerable Web 2.0 sites to fully convert to SSL, something only Gmail applies at present. Facebook responded to the release of Firesheep by announcing (via Forbes here) plans to fully encrypt sessions, an upgrade already announced by Hotmail prior to the release of Firesheep.

Savvy web users can protect themselves in all cases by using a VPN connection or by using browser plug-ins that force secure connections, where supported by websites as an option.

In response to the release of Firesheep, various developers have come up with tools designed to mitigate the risk of attack.

For example, an extension called BlackSheep developed by security firm Zscaler warns users that someone on their local area network is using FireSheep, as explained in our earlier article here. Butler, however, cautions that the tool is not a reliable countermeasure and fails completely to address the underlying risk highlighted by Firesheep.

"An attacker can easily hide from 'Blacksheep' by VPNing themselves or by using another tool instead of Firesheep," Butler said. "This is not a solution."

Another tool, called FireShepherd (see?), attempts to thwart Firesheep by flooding the Wi-Fi network with junk, causing the plug-in to crash. Butler is even more dismissive of this tool, comparing it to an attempt to shout louder than a drunk friend who has decided to yell out his credit card number in a bar.

"While this may prevent some people from hearing the card number, it won’t stop everyone, and will most certainly upset everyone else at the bar even further," Butler argues.

"FireShepherd provides no real security and is harmful to Facebook’s servers and the local network which it is used on. Nobody should recommend using it for any reason."

The release of Firesheep, detected by some anti-virus firms as malware, has spurred an ethical debate. Butler responds to accusations that the release of the software was either illegal or at least unethical in a blog post here. ®