A hacker group known for its ties to Moscow made at least 5 attempts to access Hillary Clinton’s emails during her time as secretary of state.

The story broke after a series of emails were released on Wednesday, in which it was revealed that hackers sent infected emails disguised as parking tickets on 3 August 2011, according to Fox News.

Hackers Linked To Russia Tried To Access Clinton Emails

Investigation still ongoing into security breach

If Clinton had printed the tickets as instructed, hackers would have been able to assume control of her machine. It is not yet known whether Clinton exposed herself to the malware.

“We have no evidence to suggest she replied to this email or that she opened the attachment,” Nick Merrill, a spokesman for Clinton’s Democratic presidential campaign told the Associated Press. “As we have said before, there is no evidence that the system was ever breached. All these emails show is that, like millions of other Americans, she received spam.”

According to security researchers the malware would have transmitted information to three servers, one of which was in Russia, should Clinton have opened a file called “Ticket.zip.” Experts say that the method was used around that time by Russia-linked hackers.

Potentially serious security breach on private email server

Had Clinton fallen into the trap, hackers would have been able to intercept communications, steal data, access the State Department network and perhaps other government networks. Researchers say that commercial anti-virus software would have detected the threat, but it is not known whether State Department security would have found the threat.

The FBI is investigating possible security breaches of Clinton’s private email server. Director James Comey told congressmen that “top people” are working “24/7” to find out whether classified information was leaked. No evidence of a breach has been found thus far.

Comey was asked whether the investigation would be influenced by politics given the fact that Clinton is a Democratic presidential runner.

“I’m not going to comment, as we never do, on any particular investigation of ours,” Comey explained. “But I can assure the American people about this, I hope they already know it about the FBI, we are three things — we’re competent, we’re independent, and we’re honest. We do all of our work that way. We don’t give a rip about politics. We follow the facts where they lead us. We do our work professionally, and we also do it in secret so that we don’t jeopardize our ability to do it well.”

Controversy could affect Clinton’s presidential bid

The risks of a top-level official routing emails through a private server have been discussed at length by security analysts and lawmakers. National Security Agency Director Michael Rogers recently acknowledged that spy agencies could see an opportunity in the use of private email accounts by the foreign ministers of Iran and Russia.

Investigators maintain that a security breach would have left evidence of malicious code on the server that they will be able to recover. The FBI believes in “the highest degree of confidence” that emails are being recovered.

According to a congressional source, Comey said that he aims to conclude the investigation before the election cycle is complete, although he will serve ten years as director. The implication is that he is free to pursue the investigation without outside pressure.

The results of the investigation could have serious implications for the race for the U.S. presidency.