In an announcement on Friday, the company said it was continuing to investigate a hacking attack on its computer systems that it first disclosed two weeks ago.
SAN FRANCISCO — Facebook said on Friday that an attack on the company’s computer systems affected 30 million users, about 20 million fewer than it had estimated earlier.
The announcement was a positive development for Facebook as it continues to investigate what was probably the most substantial breaching of its network in the company’s 14-year history.
Of the 30 million users who were affected, about half had their names and contact information like telephone numbers stolen from their Facebook profiles, the company said.
About 14 million people had their names, contact information and other personal details like location, gender, religious affiliation exposed to hackers. In some instances, hackers also gained access to users’s recent search histories. For about one million people, hackers did not gain access to profile information, the company said.
“We have been working around the clock to investigate the security issue we discovered and fixed two weeks ago so we can help people understand what information the attackers may have accessed,” Guy Rosen, vice president of product management, wrote in a blog post on Friday.
The breach was disclosed at a difficult time for Facebook. The company has spent the past year fighting the impression that it was not doing enough to protect the personal information of the more than two billion people who use the social network regularly.
In March, Facebook was hurt by revelations that Cambridge Analytica, a British consulting firm, had gained access to the private information of up to 87 million users. The company is also continuing to address concerns that disinformation on its platforms has affected elections and has even led to deaths in several countries.
