The California-based firm said Tuesday that a “highly sophisticated threat actor” broke into its network and stole its tools.
“The attacker primarily sought information related to certain government customers,” said FireEye CEO Kevin Mandia.
“I’ve concluded we are witnessing an attack by a nation with top-tier offensive capabilities,” he said.
Mandia said that the breach was “different from the tens of thousands of incidents we have responded to throughout the years.”
“The attackers tailored their world-class capabilities specifically to target and attack FireEye. They used a novel combination of techniques not witnessed by us or our partners in the past,” he added.
FireEye and the FBI are investigating the claimed hack.
The firm, set up in 2004, has been at the forefront of investigating attacks in cyberspace against companies throughout the world.
FireEye formerly accused the Russian military of hacking Ukraine’s energy grid in 2015 and 2016.
Two years ago, it also accused Iran of engaging in activities included “anti-Saudi, anti-Israeli, and pro-Palestinian themes.”
The allegations prompted Facebook to target hundreds of accounts allegedly tied to Iran and Russia.
The social media giant “removed multiple pages, groups and accounts for coordinated inauthentic behavior on Facebook and Instagram.”
In another move, Facebook labeled Iran’s Press TV, Russia’s Sputnik, and China’s Xinhua News Agency as “state-media,” earlier this year.
The move against theses media came after they published articles and videos of widespread US protests against US police violence and systemic racism in the United States following the death of George Floyd, an unarmed black man at the hands of a white officer in Minneapolis.
Facebook, however, refused to label US President Donald Trump’s posts which many people argued were fomenting violence against protesters who had taken to the streets in anger at Floyd’s death.
Mark Zuckerberg, Facebook’s chief executive, repeatedly defended himself by claiming that it was not the responsibility of his company to police political speech.