Yahoo slow to invest in security defences, sources say

San Francisco

SIX years ago, Yahoo's computer systems and customer e-mail accounts were penetrated by Chinese military hackers. Google and a number of other technology companies were also hit.

Google co-founder Sergey Brin regarded the attack on his company's systems as a personal affront and responded by making security a top corporate priority. Google hired hundreds of security engineers with six-figure signing bonuses, invested hundreds of millions of dollars in security infrastructure and adopted a new internal motto, "Never again", to signal that it would never again allow anyone - be they spies or criminals - to hack into Google customers' accounts.