Tesco PLC (LSE:TSCO) got its online grocery system back up and running on Monday after it was taken out of action over most of the weekend due to a cyber attack.
On Saturday, the website and app of Britain's largest supermarket group crashed, following what the company later said were attempts by unknown parties "to interfere with our systems".
Tesco said attempts to compromise its systems were made on Friday night and into Saturday morning, with shoppers first reporting issues with tracking deliveries and an inability to make changes to orders on Saturday morning.
With Tesco taking 1.3mln online orders a week and making annual online grocery revenues of £6.3bn, an outage for two days could cost the supermarket over £30mln.
@Tesco well done for getting your website and app up and running; my favourites have disappeared from the app so is my personal data safe?
— Virginia McClane (@VirginiaMcClane) October 25, 2021
"There is no reason to believe that this issue impacts customer data and we continue to take ongoing action to make sure all data stays safe," a Tesco spokesperson said on Sunday.
"Since yesterday, we've been experiencing disruption to our online grocery website and app.
"An attempt was made to interfere with our systems which has caused problems with the search function on the site. We're working hard to fully restore all services and apologise for the inconvenience."