The argument that Russia’s attempts to manipulate the 2016 presidential election are “fake news” or Cold War posturing has crumbled under an avalanche of evidence.

A year ago, this NSA document, leaked by now-jailed NSAA employee Reality Winner and published by  The Intercept, provided a reality check.

Is the document authentic? Yes. But The Intercept cautioned against over-interpretation.

While the document provides a rare window into the NSA’s understanding of the mechanics of Russian hacking, it does not show the underlying “raw” intelligence on which the analysis is based. A U.S. intelligence officer who declined to be identified cautioned against drawing too big a conclusion from the document because a single analysis is not necessarily definitive.

Some of its findings seem solid. The NSA documentstates unequivocally in its summary statement that it was Russian military intelligence, specifically the Russian General Staff Main Intelligence Directorate, or GRU, that conducted the cyber attacks described in the document.

Vikram Thakur, a senior research manager at Symantec’s Security Response Team, told The Intercept:

in cases like this the “quantity of exfiltrated data is only limited by the controls put in place by network administrators.” Data theft of this variety is typically encrypted, meaning anyone observing an infected network wouldn’t be able to see what exactly was being removed but should certainly be able to tell something was afoot, Williams added.

The NSA documents suggests that President Obama’s personal warning to President Vladimir Putin in September 2016 not to hack the election, went unheeded.

“The fact that this is occurring in October is troubling,” said one senior law enforcement official with significant cyber expertise. “In August 2016 warnings went out from the FBI and DHS to those agencies. This was not a surprise. This was not hard to defend against. But you needed a commitment of budget and attention.”

Source: Top-Secret NSA Report Details Russian Hacking Effort Days Before 2016 Election