The state-sponsored Lazarus Group is a “persistent, advanced threat” and has been posing as other people to hunt for victims, the social network warned.
Cybersecurity experts say the shadowy hacker group is linked to Kim Jong-un’s regime, and is widely believed to be behind a series of high-profile attacks on businesses and government targets around the world.
The announcement from Facebook came on the same day the United States formally blamed the rogue state for the WannaCry ransomware attacks, which crippled NHS systems earlier this year.
A statement issued by the social network yesterday said: “Last week, Facebook, Microsoft, and other members of the security community took joint action to disrupt the activities of a persistent, advanced threat group commonly referred to as ZINC, or the Lazarus Group.
“Our security team monitors Facebook’s platform for these kinds of activities, investigates the actors involved and disrupts their operations, working both on our own and in coordination with other companies.
“In this case, we deleted accounts operated by this group to make it harder for them to conduct their activities.
“Similar to other threat groups, they largely used personal profiles and pretended to be other people in order to do things like learning about others and building relationships with potential targets.
“We also notified people who may have been in contact with these accounts and gave suggestions to enhance their account security, as we have done in the past about other threat groups.”
However Facebook said its actions were nothing to do with the WannaCry attack, which infected computers in more than a third of NHS trusts in England.
The malware encrypted the victim’s important files and demanded a ransom of between $300 and $600 in bitcoin to unlock them.
Following the attack, the UK’s National Cyber Security Centre concluded it was “highly likely” the Lazarus Group was responsible.
However the United States has not publicly accused the hermit kingdom until this week.
The Lazarus Group is widely believed to have perpetrated the Sony Pictures hack in 2014, in which personal details of thousands of employees as well as unreleased films were stolen.
Under the name the Guardians of Peace, the group also threatened terrorist attacks on any cinemas which screened The Interview, a then-unreleased Sony film depicting the assassination of Kim Jong-un.
The North has always denied any link to the group and responsibility for either the WannaCry or Sony attacks.