Yahoo has fixed a glitch in its security software which allowed hackers access to 450,000 email addresses and passwords which they then leaked online last week.
The beleaguered technology giant claims it has now solved the problem.
In a statement on the company blog, a spokesman for Yahoo wrote: “Yahoo! recently confirmed that an older file containing approximately 450,000 email addresses and passwords was compromised. The compromised information was provided by writers who had joined Associated Content prior to May 2010, when it was acquired by Yahoo. (Associated Content is now the Yahoo! Contributor Network.) This compromised file was a standalone file that was not used to grant access to Yahoo systems and services.
“We have taken swift action and have now fixed this vulnerability, deployed additional security measures for affected Yahoo! users, enhanced our underlying security controls and are in the process of notifying affected users. In addition, we will continue to take significant measures to protect our users and their data.”
Hackers belonging to a group called D33Ds Company posted the Yahoo account information on a public website in what they described as "a wake-up call" last week.
David Emm, senior security researcher at Kaspersky, said: "Unfortunately, many people use the same password for multiple online accounts. This brings with it the risk that a compromise of one account puts all their accounts at risk. We would urge everyone to use a unique, complex password for all online accounts, i.e. one that is at least eight characters and mixes letters, numbers and symbols."