Donald Trump on Monday night questioned the widely held belief that Russian intelligence agents were behind the Democratic National Committee hack.
"I don't know if we know it was Russia who broke into the DNC," the GOP presidential candidate said when the first presidential debate turned to the topic of cybersecurity. "She keeps saying 'Russia, Russia, Russia,' and maybe it was. It could be Russia but it could be China, could also be lots of other people. It could be someone sitting on their bed that weighs 400 pounds."
While Trump might not be certain about the source of the attack, the consensus is pretty strong among law enforcement and analysts: Russian intelligence was almost certainly behind it, or at least involved.
Last week, U.S. Director of National Intelligence James Clapper — in his most explicit comments to date — suggested Russia was behind the breach and subsequent leaks, The Wall Street Journal reported. Clapper pointed out that the Russian spies have targeted the U.S. since the 1960s and that the most recent attacks perhaps seem more shocking because they employed cybertools.
Also, a cybersecurity firm employed by the DNC to investigate the breach found evidence of two Russian intelligence-affiliated groups present in the DNC network in May.
To be sure, the FBI is still investigating the DNC hack — believed to have taken place over a year-long period — which came to light in April with the publication of leaked emails sufficiently embarrassing and well-timed to force the resignation of key DNC staffers ahead of the Democratic National Convention.
The White House has tiptoed around blaming Russian President Vladimir Putin directly, citing the ongoing FBI investigation, but President Barack Obama has said cyberexperts implicated Russia in the hack and that Russia stands to benefit from a Trump White House win.
Cybersecurity experts have warned that if in fact Russia is found to be behind the breach and subsequent leaks of information, that infiltration would represent a paradigm shift in cyberwarfare.
"There's been a line that has been crossed, and there has to be some type of response if, indeed, there is a nation-state responsible," said Chris Finan, a former White House cybersecurity director in the Obama administration.
The DNC intrusion is evidence that data breaches are becoming a tool of global and geopolitical influence, wielded by motivated state actors, security experts said.
From the Chelsea Manning leak of hundreds of thousands of secret military and diplomatic documents to WikiLeaks in 2010, to the Edward Snowden NSA scandal that in 2013, to North Korean hack of Sony in 2014, what used to be considered a nuisance or an embarrassment has become much more serious.
"One thing that everyone's talking about is a weaponization of data," said Danny Rogers, chief executive officer of cybersecurity intelligence firm Terbium, which was not involved in the DNC hack investigation.
During Monday night's debate, Clinton reiterated her contention that Russian spies were responsible for the attack.
"Putin is playing a very tough, long game here," the Democratic presidential nominee said. "And one of the things he's done is to let loose cyberattackers to hack into government files, to personal files, the Democratic National Committee."