Yahoo has revealed that hackers stole information from approximately 500 million users in what is now being seen as the largest disclosed cyber-breach in history.
The hack orignally occured in 2014 but has only now been made public.
The breach compromised personal information, including names and emails, as well as "unencrypted security questions and answers".
Respoding to news of the breach and the impact on users, James Maude, senior security engineer at Avecto said:
“Users should be concerned about is how a behemoth of the internet failed to notice this for such a long period of time. This is especially concerning as Yahoo promised to have overhauled security following the allegations of government interference in the Snowdon documents.
“For the consumer, it is time to consider the impact of this breach and evaluate what data they stored on their Yahoo account. Users of Yahoo mail services should be the most vigilant as their email account maybe the gateway to access many online services, from banking sites to dating websites, containing highly personal information. It is important to reset passwords that may be at risk and consider what other accounts were linked to Yahoo services, such as Flickr, that may store private family photos.
“Time and time again we see organisations failing to notice suspicious activity occurring in their environment and on their endpoints as they are reliant on failing detection solutions that simply can’t spot unique targeted attacks. As Yahoo were recently acquired by Verizon who annually publish the industry leading report on data breaches, there may well be a few awkward conversations happening internally this week.”