The full-scale of a 2013 data breach at Yahoo has only now become apparent after the internet company finally admitted that all 3billion of its user accounts had been breached by hackers – tripling earlier estimates which have risen steadily from 500 million to in excess of 1 billion.
The revelation will heap further pressure on Verizon Communications which pressed ahead with its takeover even after the largest data theft in history came to light, massively increasing its legal exposure to future compensation claims.
Yahoo is already subject to in excess of 41 consumer class-action lawsuits in the US, a number which could now swell as many more shareholders and Yahoo account holders find themselves in a position to seek redress.
On Tuesday Yahoo said that ‘recently obtained intelligence’ had come to light proving that all user accounts had been affected – although the stolen data did not extend to unencrypted passwords, payment card details or bank account information.
External academics warn however that these details were protected by poor encryption techniques, making them easy to crack and exposing those affected to the possibility of having further accounts compromised.
Verizon slashed $350m off its purchase price back in February when the scandal first broke, finally sealing the deal in July but may now take legal steps to claim back further sums.