NSA Running a Massive IDS on the Internet Backbone

The latest story from the Snowden documents, co-published by the New York Times and ProPublica, shows that the NSA is operating a signature-based intrusion detection system on the Internet backbone:

In mid-2012, Justice Department lawyers wrote two secret memos permitting the spy agency to begin hunting on Internet cables, without a warrant and on American soil, for data linked to computer intrusions originating abroad — including traffic that flows to suspicious Internet addresses or contains malware, the documents show. The Justice Department allowed the agency to monitor only addresses and “cybersignatures” ­– patterns associated with computer intrusions — that it could tie to foreign governments. But the documents also note that the N.S.A. sought to target hackers even when it could not establish any links to foreign powers.

To me, the big deal here is 1) the NSA is doing this without a warrant, and 2) that the policy change happened in secret, without any public policy debate.

The effort is the latest known expansion of the N.S.A.’s warrantless surveillance program, which allows the government to intercept Americans’ cross-border communications if the target is a foreigner abroad. While the N.S.A. has long searched for specific email addresses and phone numbers of foreign intelligence targets, the Obama administration three years ago started allowing the agency to search its communications streams for less-identifying Internet protocol addresses or strings of harmful computer code. […] To carry out the orders, the F.B.I. negotiated in 2012 to use the N.S.A.’s system for monitoring Internet traffic crossing “chokepoints operated by U.S. providers through which international communications enter and leave the United States,” according to a 2012 N.S.A. document. The N.S.A. would send the intercepted traffic to the bureau’s “cyberdata repository” in Quantico, Virginia.

Ninety pages of NSA documents accompany the article. Here is a single OCRed PDF of them all.

Jonathan Mayer was consulted on the article. He gives more details on his blog, which I recommend you all read.

In my view, the key takeaway is this: for over a decade, there has been a public policy debate about what role the NSA should play in domestic cybersecurity. The debate has largely presupposed that the NSA’s domestic authority is narrowly circumscribed, and that DHS and DOJ play a far greater role. Today, we learn that assumption is incorrect. The NSA already asserts broad domestic cybersecurity powers. Recognizing the scope of the NSA’s authority is particularly critical for pending legislation.

This is especially important for pending information sharing legislation, which Mayer explains.

The other big news is that ProPublica’s Julia Angwin is working with Laura Poitras on the Snowden documents. I expect that this isn’t the last artcile we’re going to see.

EDITED TO ADD: Others are writing about these documents. Shane Harris explains how the NSA and FBI are working together on Internet surveillance. Benjamin Wittes says that the story is wrong, that “combating overseas cybersecurity threats from foreign governments” is exactly what the NSA is supposed to be doing, and that they don’t need a warrant for any of that. And Marcy Wheeler points out that she has been saying for years that the NSA has been using Section 702 to justify Internet surveillance.

EDITED TO ADD (6/5): Charlie Savage responds to Ben Wittes.

Posted on June 5, 2015 at 7:42 AM • 45 Comments