Facebook has no plans to notify 533 million users affected by data leak

The company says it is not confident that it has full visibility on which users will need to be informed

Social media giant Facebook does not intend to notify over a half-billion users whose personal details have leaked online on a hacking forum.

A Facebook spokesperson told Reuters that the company was not confident that it had full visibility on which users would need to be informed. The spokesperson added that the company also took into account that it was not possible for users to fix the issue at their end and that the "data was publicly available".

The data leak exposed personal details of more than 533 million Facebook users from 106 countries, including over 44 million records on users in Egypt, 39 million in Tunisia, 32 million in the US and 11 million in the UK. It includes their full names, phone numbers, gender, date of birth, location, relationship status and email address.

The Facebook spokesman refused to discuss the company's ongoing conversations with regulators but said it was in contact to answer their questions.

In a blog post on Tuesday, Mike Clark, product management director at Facebook, explained that malicious actors had accessed the user data "not through hacking Facebook systems" but by scraping it from people's Facebook profiles prior to September 2019.

According to Clark, the hackers used Facebook's contact importer feature that was designed to help people easily find their friends on Facebook services using their contact lists.

Clark said that the vulnerable feature, which allowed anyone to scrape data from the Facebook platform, had been fixed in 2019 and no longer exists.

The company also said that malicious actors obtained a limited set of data about the users and that it did not include sensitive details, such as passwords, health or financial information.

"While we can't always prevent data sets like these from recirculating or new ones from appearing, we have a dedicated team focused on this work," Clark added.

Facebook advised users to take regular privacy check-ups on the platform and to also update settings for "How People Find and Contact You" feature on the platform.

The news of Facebook data leak comes at the time when the company is facing fresh scrutiny from a new UK competition watchdog that wants to curb the massive market powers of big technology firms.

The UK's Digital Markets Unit (DMU), which was officially launched on Wednesday, is set to crack down on Big Tech's unfair practices.

It is tasked with drafting potential codes of conduct for companies such as Google and Facebook and to enforce a competition regime that will cover digital businesses with "considerable market power".

The DMU will be based inside the Competition and Markets Authority (CMA) and will be "unashamedly pro-competition", according to the UK's Business Secretary Kwasi Kwarteng.