Yahoo confirmed on Wednesday that a cyber-attack that took place in 2013 resulted in the theft of personal data from around one billion Yahoo account holders. The disclosure comes just months after Yahoo revealed that some 500 million user accounts had been breached as part of a 2014 hack. The successive announcements have dramatically destablised Yahoo’s plans to offload its core assets to Verizon, in a deal that was struck in July prior to the company’s first disclosure.

Attack and defence

The disclosure has left Verizon’s in-house lawyers scrambling to see if they can salvage the company’s planned purchase of Yahoo’s core assets for $4.8bn without exposing the company to unacceptable litigation risks. Meanwhile, it took Los Angeles law firm Capstone Law APC less than 12 hours to launch its own class action lawsuit against Yahoo following the company’s most recent admission. Documents filed in a San Francisco federal court read: ‘Despite Yahoo’s assurance, Yahoo has failed, and continues to fail, to provide adequate protection of its users’ personal and confidential information.’  

Sources: Wall Street Journal; Financial Times