And both security experts also say that the nature of the leak and the type of material leaked indicate that a state player is behind it: almost certainly Russia, they conclude.
The leak of material dating back to 2013 was done by a group calling itself Shadow Brokers that claimed it had hacked Equation Group, a highly sophisticated outfit that has been strongly suspected of being an offshoot of the NSA.
The post also had links to what were claimed to be advanced hacking tools.
"While we cannot surmise the attacker's identity or motivation nor where or how this pilfered trove came to be, we can state that several hundred tools from the leak share a strong connection with our previous findings from the Equation group," the company said.
Snowden said the leak was most likely "a warning that someone can prove US responsibility for any attacks that originated from this malware server".
He added that it looked like somebody was "sending a message that an escalation in the attribution game could get messy fast".
"NSA malware staging servers getting hacked by a rival is not new. A rival publicly demonstrating they have done so is," Snowden said.
The hacks of emails from the Democratic National Committee led to the resignation of its chairperson Debbie Wasserman Schultz and a few other officials. A separate break-in resulted in a dump of personal information of serving Democrats, all of it from material that had been exfiltrated from the Democratic Congressional Campaign Committee.
Aitel said the timing of the leak, the mention of corruption and elections in the release, the fact that it had been kept quiet for three years, and the risk of annoying the Equation Group this much all pointed to a big player: "Level of difficulty: Very Experienced Nation State."
WikiLeaks has claimed it has the same material as that stolen by Shadow Brokers and has said it will post it after it is suitably sanitised. The group was criticised recently by Snowden for releasing material from the DNC that included personal details.