Last weekend, the Sunday Times published a front-page story (full text here), citing anonymous British sources claiming that both China and Russia have copies of the Snowden documents. It's a terrible article, filled with factual inaccuracies and unsubstantiated claims about both Snowden's actions and the damage caused by his disclosure, and others have thoroughly refuted the story. I want to focus on the actual question: Do countries like China and Russia have copies of the Snowden documents?

I believe the answer is certainly yes, but that it's almost certainly not Snowden's fault.

Snowden has claimed that he gave nothing to China while he was in Hong Kong, and brought nothing to Russia. He has said that he encrypted the documents in such a way that even he no longer has access to them, and that he did this before the US government stranded him in Russia. I have no doubt he did as he said, because A) it's the smart thing to do, and B) it's easy. All he would have had to do was encrypt the file with a long random key, break the encrypted text up into a few parts and mail them to trusted friends around the world, then forget the key. He probably added some security embellishments, but—regardless—the first sentence of the Times story simply makes no sense: "Russia and China have cracked the top-secret cache of files..."

But while cryptography is strong, computer security is weak. The vulnerability is not Snowden; it's everyone who has access to the files.

The vulnerability is not Snowden; it’s everyone who has access to the files.

First, the journalists working with the documents. I've handled some of the Snowden documents myself, and even though I'm a paranoid cryptographer, I know how difficult it is to maintain perfect security. It's been open season on the computers of the journalists Snowden shared documents with since this story broke in July 2013. And while they have been taking extraordinary pains to secure those computers, it's almost certainly not enough to keep out the world's intelligence services.

There is a lot of evidence for this belief. We know from other top-secret NSA documents that as far back as 2008, the agency's Tailored Access Operations group has extraordinary capabilities to hack into and "exfiltrate" data from specific computers, even if those computers are highly secured and not connected to the Internet.

These NSA capabilities are not unique, and it's reasonable to assume both that other countries had similar capabilities in 2008 and that everyone has improved their attack techniques in the seven years since then. Last week, we learned that Israel had successfully hacked a wide variety of networks, including that of a major computer antivirus company. We also learned that China successfully hacked US government personnel databases. And earlier this year, Russia successfully hacked the White House's network. These sorts of stories are now routine.

I believe that both China and Russia had access to all the files that Snowden took well before Snowden took them because they've penetrated the NSA networks where those files reside.

Which brings me to the second potential source of these documents to foreign intelligence agencies: the US and UK governments themselves. I believe that both China and Russia had access to all the files that Snowden took well before Snowden took them because they've penetrated the NSA networks where those files reside. After all, the NSA has been a prime target for decades.

Those government hacking examples above were against unclassified networks, but the nation-state techniques we're seeing work against classified and unconnected networks as well. In general, it's far easier to attack a network than it is to defend the same network. This isn't a statement about willpower or budget; it's how computer and network security work today. A former NSA deputy director recently said that if we were to score cyber the way we score soccer, the tally would be 462–456 twenty minutes into the game. In other words, it's all offense and no defense.

In this kind of environment, we simply have to assume that even our classified networks have been penetrated. Remember that Snowden was able to wander through the NSA's networks with impunity, and that the agency had so few controls in place that the only way they can guess what has been taken is to extrapolate based on what has been published. Does anyone believe that Snowden was the first to take advantage of that lax security? I don't.

We simply have to assume that even our classified networks have been penetrated.

This is why I find allegations that Snowden was working for the Russians or the Chinese simply laughable. What makes you think those countries waited for Snowden? And why do you think someone working for the Russians or the Chinese would go public with their haul?

I am reminded of a comment made to me in confidence by a US intelligence official. I asked him what he was most worried about, and he replied: "I know how deep we are in our enemies' networks without them having any idea that we're there. I'm worried that our networks are penetrated just as deeply."

Seems like a reasonable worry to me.

The open question is which countries have sophisticated enough cyberespionage operations to mount a successful attack against one of the journalists or against the intelligence agencies themselves. And while I have my own mental list, the truth is that I don't know. But certainly Russia and China are on the list, and it's just as certain they didn't have to wait for Snowden to get access to the files. While it might be politically convenient to blame Snowden because, as the Sunday Times reported an anonymous source saying, "we have now seen our agents and assets being targeted," the NSA and GCHQ should first take a look into their mirrors.