'Sidejacking' Tool Unleashed

Lets attackers sniff and access Web accounts over WiFi

LAS VEGAS -- Black Hat USA -- Here's another reason not to use WiFi unprotected: Hackers can "sidejack" your machine and access your Web accounts, researchers demonstrated here today as part of the "Simple Solutions to Complex Problems from the Lazy Hacker's Handbook." (See Black Hat: How to Hack IPS Signatures.)

Robert Graham, CEO of Errata Security, showed -- and released -- his new Hamster tool, a more powerful version of his Ferret WiFi sniffer that can grab users' Gmail, Yahoo, and other online accounts. Hamster basically clones the victim's cookies by sniffing their session IDs and controlling their Website accounts. (See Joke's on Me and Tool Uncovers Inadvertent 'Chatter'.)

"You can be in a café and see a list of people browsing [over WiFi]. And you can highjack and clone their Gmail system, for example, Graham says. "We know it's theoretically possible, so we wanted to prove it... This is very powerful because it's so easy to do."

The tool doesn't require grabbing passwords, just the cookies and URL trail the user leaves behind. "Hamster is a proxy, just like Squid" HTTP proxy software, he says. "I didn't want to use Squid because it's a bigger program and I wanted to create a small kit I can give people to download."

Hamster only runs on Windows, and Graham says the code is still a bit finicky, but it proves that attackers can not only sniff, but grab, a victim's online accounts.

Graham says Hamster doesn't let an attacker actually see the victim writing an email, but the "state information" so that the attacker can then pose as the unsuspecting victim -- and read, send, and receive email on his behalf.

"The cool thing with Ferret is that a lot these cookies are persistent, so I can copy them now, go home and load them into Hamster, and most will still work," he says.

Graham tested his tool at Black Hat yesterday, but he lamented that it wasn't easy to find a large number of users here who venture into WiFi unprotected. "Everyone is getting so paranoid around here."

Besides the obvious "don't use open WiFi recommendation," Graham says users should routinely log out of their Web sessions, which wipes out their cookie trail and thus dead-ends the Hamster attacker.

— Kelly Jackson Higgins, Senior Editor, Dark Reading

About the Author(s)

Kelly Jackson Higgins, Editor-in-Chief, Dark Reading

Kelly Jackson Higgins is the Editor-in-Chief of Dark Reading. She is an award-winning veteran technology and business journalist with more than two decades of experience in reporting and editing for various publications, including Network Computing, Secure Enterprise Magazine, Virginia Business magazine, and other major media properties. Jackson Higgins was recently selected as one of the Top 10 Cybersecurity Journalists in the US, and named as one of Folio's 2019 Top Women in Media. She began her career as a sports writer in the Washington, DC metropolitan area, and earned her BA at William & Mary. Follow her on Twitter @kjhiggins.

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