"Counterfeit products are a routine threat for the electronics industry. However, the more sinister specter of an electronic Trojan horse, lurking in the circuitry of a computer or a network router and allowing attackers clandestine access or control, was raised again recently by the F.B.I. and the Pentagon.Dan Wallach makes the point over at Freedom to Tinker that the key story here is the integrity of the supply chain.
The new law enforcement and national security concerns were prompted by Operation Cisco Raider, which has led to 15 criminal cases involving counterfeit products bought in part by military agencies, military contractors and electric power companies in the United States. Over the two-year operation, 36 search warrants have been executed, resulting in the discovery of 3,500 counterfeit Cisco network components with an estimated retail value of more than $3.5 million, the F.B.I. said in a statement.
The F.B.I. is still not certain whether the ring’s actions were for profit or part of a state-sponsored intelligence effort. The potential threat, according to the F.B.I. agents who gave a briefing at the Office of Management and Budget on Jan. 11, includes the remote jamming of supposedly secure computer networks and gaining access to supposedly highly secure systems. Contents of the briefing were contained in a PowerPoint presentation leaked to a Web site, Above Top Secret."
"The really interesting story is all about the supply chain. Consider how you might buy yourself a new Mac. You could go to your local Apple store. Or you could get it from any of a variety of other stores, who in turn may have gotten it from Apple directly or may have gone through a distributor. Apparently, for Cisco gear, it’s much more complicated than that. The U.S. government buys from “approved” vendors, who might then buy from multiple tiers of sub-contractors. In one case, one person bought shady gear from eBay and resold it to the government, moving a total of $1M in gear before he was caught. In a more complicated case, Lockheed Martin won a bid for a U.S. Navy project. They contracted with an unauthorized Cisco reseller who in turn contracted with somebody else, who used a sub-contractor, who then directly shipped the counterfeit gear to the Navy. (The slides say that $250K worth of counterfeit gear was sold; duplicate serial numbers were discovered.)
Why is this happening? The Government wants to save money, so they look for contractors who can give them the best price, and their contracts allow for subcontracts, direct third-party shipping, and so forth. There is no serious vetting of this supply chain by either Cisco or the government. Apparently, Cisco doesn’t do direct sales except for high-end, specialized gear. You’d think Cisco would follow the lead of the airline industry, among others, and cut out the distributors to keep the profit for themselves.
Okay, on to the speculation. Both the New York Times and the FBI presentation concern themselves with Trojan Horses. Even though there’s no evidence that any of this counterfeit gear was actually malicious, the weak controls in the supply chain make it awfully easy for such compromised gear to be sold into sensitive parts of the government, raising all the obvious concerns.
Consider a recent paper by U. Illinois’s Sam King et al. where they built a “malicious processor”. The idea is pretty clever. You send along a “secret knock” (e.g., a network packet with a particular header) which triggers a sensor that enables “shadow code” to start running alongside the real operating system. The Illinois team built shadow code that compromised the Linux login program, adding a backdoor password. After the backdoor was tripped, it would disable the shadow code, thus going back to “normal” operation.
The military is awfully worried about this sort of threat, as well they should be. For that matter, so are voting machine critics. It’s awfully easy for “stealth” malicious behavior to exist in legitimate systems, regardless of how carefully you might analyze or test it. Ken Thompson’s classic paper, Reflections on Trusting Trust, shows how he designed a clever Trojan Horse for Unix. [Edit: it's unclear that it ever got released into the wild.]
In summary, it’s probably a good thing, from the perspective of the U.S. military, to discover that their supply chain is allowing counterfeit gear into production. This will help them clean up the supply chain, and will also provide an extra push to consider just how much they trust the sources of their equipment to ship clean software and hardware."