When Dreamcasts attack
Inside-out network hacking with toys
LAS VEGAS -- Cyberpunks will be toting cheap game consoles on their utility belts this fall if they follow the lead of a pair of white hat hackers who demonstrated Wednesday how to turn the defunct Sega Dreamcast into a disposable attack box designed to be dropped like a bug on corporate networks during covert black bag jobs.
The "phone home" technique presented by Aaron Higbee of Foundstone and Chris Davis from RedSiren Technologies at the Black Hat Briefings here takes advantage of the fact that firewalls effective in blocking entry into a private network, are generally permissive in allowing connections the other way around.
Higbee and Davis perform penetration tests, and developed their game box cum attack tool after finding themselves more than once with physical access to a client's facilities -- posing as an employee in once case, crawling through a drop ceiling in another -- but without a way to leverage that access into remote control of the company's network.
"It's not that hard to get into an organization for one or two minutes," said Higbee.
They chose the Dreamcast for its small size, availability of an Ethernet adapter, and affordability -- the console was discontinued last year, and now sells used for under $100 on eBay. Loaded with custom Linux-based software and covertly plugged into a spare network port under a desk or above a ceiling, the harmless-looking toy becomes the enemy within, probing the company firewall for a way out to Internet.
The box cycles through the ports used for common services like SSH, Web surfing, and e-mail, which tend to be permitted by firewall configurations. Failing that, it tries getting "ping" packets out to the Internet, and finally looks for proxy servers bridging the network to the outside world.
Whatever it finds, it uses to establish a tunnel through the firewall to the intruder's home machine. "Most organizations focus on the perimeter," said Davis. "Once you get through the outside, there's a soft chewy center."
The pair suggested some techniques for mitigating the risk of dropped-in hardware -- restricting the LAN to pre-assigned MAC addresses, for one -- but said that ultimately, there may be little an organization can do to prevent an attacker with physical access from setting up a covert channel home.
The pair plan to release their Dreamcast software on their website next month, along with similar code they developed for the handheld Compaq iPAQ, and a bootable CD ROM designed to be slipped into print servers and other kiosk PCs.
While useful, they note that the other platforms lack at least one of the Dreamcast's virtues. "It's innocuous. It looks like a toy," said Davis. "If you bring it into a company, they're going to go, 'Wow, look at the toy!'"
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