BREAKING NEWS: FireEye, one of the world's biggest cyber security firms, is HACKED by 'world class Russian hackers'

FireEye, one of the world's largest cyber security firms, announced on Tuesday that it had been hacked, allegedly by Russia. 

The company announced the breach in a blog post. It did not say when the hack happened or who it applied to but that it was 'state sponsored'. 

FireEye didn't label Russia as the culprit but a source told The Wall Street Journal they are most likely the country behind it. 

The company is now working with the FBI. According to a source close to the investigation, the hackers were extraordinarily precise. 

'This was a sniper shot that got through,' they said. 

FireEye, one of the largest cyber security firms in the world, has been hacked 

According to a source close to the investigation, the hackers were extraordinarily precise. 'This was a sniper shot that got through,' they said.

Kevin Mandia, FireEye's CEO who is also a former Air Force Officer, said the attack was 'top-tier'. 

'Recently, we were attacked by a highly sophisticated threat actor, one whose discipline, operational security, and techniques lead us to believe it was a state-sponsored attack.  

'We are witnessing an attack by a nation with top-tier offensive capabilities. 

'This attack is different from the tens of thousands of incidents we have responded to throughout the years,' he wrote in the blog post.  

So far, none of the information that has been compromised has been used but Mandia said there was no way of knowing what the hackers wanted to do with it.  

FireEye CEO Kevin Mandia said the attack was carried out by 'world class' operatives 

The hackers accessed the company's Red Tools which, they say, 'apply well-known and documented methods that are used by other red teams around the world.' 

'It’s important to note that FireEye has not seen these tools disseminated or used by any adversaries, and we will continue to monitor for any such activity along with our security partners,' Mandia said. 

The company has issued hundreds of counter measures to try to circumvent any damage. 

FireEye's clients include Sony and Equifax. The company is widely regarded as being the best in the world for providing security measures. 

An FBI spokesman said in a statement: 'The FBI is investigating the incident and preliminary indications show an actor with a high level of sophistication consistent with a nation state.

'It is important to note that our adversaries are continuously looking for US networks to exploit.

'That is why we are focused on imposing risk and consequences on malicious cyber actors, so they think twice before attempting an intrusion in the first place; why we are focused on quickly responding to victims and providing organizations with the information. 

'They need to defend their networks; and we are encourage anyone that notices suspicious activity to notify the FBI or the USSS.'

FireEye is based in California and is worth $3.5billion.