More than a year has passed since Bloomberg Businessweek grabbed the lapels of the cybersecurity world with a bombshell claim: that Supermicro motherboards in servers used by major tech firms, including Apple and Amazon, had been stealthily implanted with a chip the size of a rice grain that allowed Chinese hackers to spy deep into those networks. Apple, Amazon, and Supermicro all vehemently denied the report. The NSA dismissed it as a false alarm. The Defcon hacker conference awarded it two Pwnie Awards, for "most overhyped bug" and "most epic fail." And no follow-up reporting has yet affirmed its central premise.

But even as the facts of that story remain unconfirmed, the security community has warned that the possibility of the supply chain attacks it describes is all too real. The NSA, after all, has been doing something like it for years, according to the leaks of whistle-blower Edward Snowden. Now researchers have gone further, showing just how easily and cheaply a tiny, tough-to-detect spy chip could be planted in a company's hardware supply chain. And one of them has demonstrated that it doesn't even require a state-sponsored spy agency to pull it off—just a motivated hardware hacker with the right access and as little as $200 worth of equipment.

"It’s not magical. It’s not impossible. I could do this in my basement." Monta Elkins, FoxGuard

At the CS3sthlm security conference later this month, security researcher Monta Elkins will show how he created a proof-of-concept version of that hardware hack in his basement. He intends to demonstrate just how easily spies, criminals, or saboteurs with even minimal skills, working on a shoestring budget, can plant a chip in enterprise IT equipment to offer themselves stealthy backdoor access. (Full disclosure: I'll be speaking at the same conference, which paid for my travel and is providing copies of my forthcoming book to attendees.) With only a $150 hot-air soldering tool, a $40 microscope, and some $2 chips ordered online, Elkins was able to alter a Cisco firewall in a way that he says most IT admins likely wouldn't notice, yet would give a remote attacker deep control.

"We think this stuff is so magical, but it’s not really that hard," says Elkins, who works as "hacker in chief" for the industrial-control-system security firm FoxGuard. "By showing people the hardware, I wanted to make it much more real. It’s not magical. It’s not impossible. I could do this in my basement. And there are lots of people smarter than me, and they can do it for almost nothing."

A Fingernail in the Firewall

Elkins used an ATtiny85 chip, about 5 millimeters square, that he found on a $2 Digispark Arduino board; not quite the size of a grain of rice, but smaller than a pinky fingernail. After writing his code to that chip, Elkins desoldered it from the Digispark board and soldered it to the motherboard of a Cisco ASA 5505 firewall. He used an inconspicuous spot that required no extra wiring and would give the chip access to the firewall's serial port.

The image below gives a sense of how tough spotting the chip would be amidst the complexity of a firewall's board—even with the relatively small, 6- by 7-inch dimensions of an ASA 5505. Elkins suggests he could have used an even smaller chip but chose the ATtiny85 because it was easier to program. He says he also could have hidden his malicious chip even more subtly, inside one of several radio-frequency shielding "cans" on the board, but he wanted to be able to show the chip's placement at the CS3sthlm conference.