Schneier - Supply-Chain Security

Earlier this month, the Pentagon stopped selling phones made by the Chinese companies ZTE and Huawei on military bases because they might be used to spy on their users.

It's a legitimate fear, and perhaps a prudent action. But it's just one instance of the much larger issue of securing our supply chains.

All of our computerized systems are deeply international, and we have no choice but to trust the companies and governments that touch those systems. And while we can ban a few specific products, services or companies, no country can isolate itself from potential foreign interference.

In this specific case, the Pentagon is concerned that the Chinese government demanded that ZTE and Huawei add "backdoors" to their phones that could be surreptitiously turned on by government spies or cause them to fail during some future political conflict. This tampering is possible because the software in these phones is incredibly complex. It's relatively easy for programmers to hide these capabilities, and correspondingly difficult to detect them.

This isn't the first time the United States has taken action against foreign software suspected to contain hidden features that can be used against us. Last December, President Trump signed into law a bill banning software from the Russian company Kaspersky from being used within the US government. In 2012, the focus was on Chinese-made Internet routers. Then, the House Intelligence Committee concluded: "Based on available classified and unclassified information, Huawei and ZTE cannot be trusted to be free of foreign state influence and thus pose a security threat to the United States and to our systems."

Nor is the United States the only country worried about these threats. In 2014, China reportedly banned antivirus products from both Kaspersky and the US company Symantec, based on similar fears. In 2017, the Indian government identified 42 smartphone apps that China subverted. Back in 1997, the Israeli company Check Point was dogged by rumors that its government added backdoors into its products; other of that country's tech companies have been suspected of the same thing. Even al-Qaeda was concerned; ten years ago, a sympathizer released the encryption software Mujahedeen Secrets, claimed to be free of Western influence and backdoors. If a country doesn't trust another country, then it can't trust that country's computer products.

But this trust isn't limited to the country where the company is based. We have to trust the country where the software is written -- and the countries where all the components are manufactured. In 2016, researchers discovered that many different models of cheap Android phones were sending information back to China. The phones might be American-made, but the software was from China. In 2016, researchers demonstrated an even more devious technique, where a backdoor could be added at the computer chip level in the factory that made the chips ­ without the knowledge of, and undetectable by, the engineers who designed the chips in the first place. Pretty much every US technology company manufactures its hardware in countries such as Malaysia, Indonesia, China and Taiwan.

We also have to trust the programmers. Today's large software programs are written by teams of hundreds of programmers scattered around the globe. Backdoors, put there by we-have-no-idea-who, have been discovered in Juniper firewalls and D-Link routers, both of which are US companies. In 2003, someone almost slipped a very clever backdoor into Linux. Think of how many countries' citizens are writing software for Apple or Microsoft or Google.

We can go even farther down the rabbit hole. We have to trust the distribution systems for our hardware and software. Documents disclosed by Edward Snowden showed the National Security Agency installing backdoors into Cisco routers being shipped to the Syrian telephone company. There are fake apps in the Google Play store that eavesdrop on you. Russian hackers subverted the update mechanism of a popular brand of Ukrainian accounting software to spread the NotPetya malware.

In 2017, researchers demonstrated that a smartphone can be subverted by installing a malicious replacement screen.

I could go on. Supply-chain security is an incredibly complex problem. US-only design and manufacturing isn't an option; the tech world is far too internationally interdependent for that. We can't trust anyone, yet we have no choice but to trust everyone. Our phones, computers, software and cloud systems are touched by citizens of dozens of different countries, any one of whom could subvert them at the demand of their government. And just as Russia is penetrating the US power grid so they have that capability in the event of hostilities, many countries are almost certainly doing the same thing at the consumer level.

We don't know whether the risk of Huawei and ZTE equipment is great enough to warrant the ban. We don't know what classified intelligence the United States has, and what it implies. But we do know that this is just a minor fix for a much larger problem. It's doubtful that this ban will have any real effect. Members of the military, and everyone else, can still buy the phones. They just can't buy them on US military bases. And while the US might block the occasional merger or acquisition, or ban the occasional hardware or software product, we're largely ignoring that larger issue. Solving it borders on somewhere between incredibly expensive and realistically impossible.

Perhaps someday, global norms and international treaties will render this sort of device-level tampering off-limits. But until then, all we can do is hope that this particular arms race doesn't get too far out of control.

This essay previously appeared in the Washington Post.

from Schneier on Security https://www.schneier.com/blog/archives/2018/05/supply-chain_se.html