Cybersecurity expert: Here's how the GOP could 'have a field day' with Hillary Clinton's email scandal
And what they find could give Clinton's political rivals the ammunition they need to forcefully attack her presidential campaign.
'Top Secret/Sensitive Compartmented Information'
Clinton, the Democratic presidential front-runner in the 2016 election, has repeatedly said as recently as late July that she was "confident" she did not send or receive classified information by email.
However, Charles McCullough, the inspector general for the US intelligence community, recently said the server potentially included hundreds of classified emails, some of which include information derived from US intelligence agencies.
And this week, McCullough told Congress that he discovered two emails that are classified as 'Top Secret/Sensitive Compartmented Information," which is one of the government's highest levels of classification. Those two emails were drawn out of a batch of 40 emails randomly selected from about 30,000 "work-related" emails Clinton turned over to the State Department.
'Hillary Clinton's big problem now is legal'
The new server was run by Bryan Pagliano, who had worked as the IT director on Hillary Clinton's campaign before joining the State Department in May 2009. In 2013 - the same year she left the State Department - Clinton hired the Denver-based company Platte River to oversee the system.
It's possible that Clinton's private server was more secure than the private email accounts of the nation's other top officials, "purely because it's a smaller target," cybersecurity expert Joe Loomis, the founder and CEO of Cybersponse, told Business Insider.
"Only she and a few other people are using it," he said.
'A serious management mistake'
And Clinton's choice to eschew the State Department's email system looks particularly egregious, given her standing within the department.
If she felt the State Department's server wasn't secure enough, she "would have been in a good position to demand change," said McGeorge, the senior security researcher at Immunity, Inc. "But if it was a problem, and you decided to use your own server, then what did you do for your department?"
And then there are the deleted emails.