The company has written that while installing the extension, AP users have reached an agreement with their own browser.
"In total, defendants compromised approximately 63,000 browsers used by Facebook users and caused over $75,000 [R1,050,000] in damages to Facebook", the company said in court documents.
Named Supertest, FQuiz, Megatest, and Pechenka, each of the four web apps were advertised toward Russian and Ukrainian-speaking audiences and enticed users with themes such as: 'Do you have royal blood?', 'You are yin.
Facebook, in its lawsuit filed on Friday, alleged that the Kiev-based entrepreneurs violated Californian and federal anti-hacking laws, and sued them for fraud and breach of Facebook's terms of service.
The hackers, Gleb Sluchevsky and Andrey Gorbachov, required users to download browser extensions to operate the quiz apps, which scraped data from Facebook pages and posted ads once they were loaded onto the browser.
"Facebook was vulnerable to very similar types of attacks, which simply means that Facebook is really good for targeting particular users with advertising, so it makes the platform so valuable", Dan Patterson, senior producer at CNET, told CBSN.
The lawsuit also said the two developers misrepresented themselves by making accounts under "aliases such as "Elena Stelmah, ' 'Amanda Pitt, ' 'Igor Kolomiiets" to register as web application developers with Facebook".
Facebook claims that the two individuals started with activities back in 2016 and continued until October 2018 when their employers, a software company called Web Sun Group, were kicked out of the platform. Last year, the BBC questioned whether Facebook had been proactive enough in addressing the malicious plugins. Also, the hackers claimed of having scraped data from 120 million accounts on Facebook.
From the implications of the lawsuit, Facebook may have allowed these hackers into their network by approving them as developers. CEO Mark Zuckerburg recently announced that Facebook is going through a major change of course, with more attention being paid to the privacy of users. The defendant may not face serious consequences, but it will give Facebook the leverage to defend itself.