Harrods did not elaborate on what the hackers had communicated to the company.
The stolen data included basic personal information, including names and contact details if they had been provided.
Some information relating to marketing preferences, loyalty cards and tie-ins to other companies was also included including Harrods co-branded cards, the company’s spokesperson said, who added “this information is unlikely to be interpreted accurately by an unauthorised third party”.
“We would like to reiterate that no payment details or order history information has been accessed and the impacted personal data remains limited to basic personal identifiers as advised previously,” they said.
This week’s data breach was not connected to attempts to hack into other Harrods systems earlier this year, the spokesperson added.
The department store first described the breach in an email to customers on Friday.
