Shoppers at SuperValu, Centra and Mace have been told to review their bank statements following a cyber attack against Irish retailer Musgrave.

Musgrave, which owns all three stores, urged customers to take the precaution amid fears that hackers may have extracted credit card and debit card numbers and expiry dates from its systems. Cardholders' names, PINs, or CVV numbers are not thought to have been exposed. Musgrave has nonetheless launched an investigation and reported the matter to Irish data privacy watchdogs at the Office of the Data Protection Commissioner, the Belfast Telegraph reports.

SuperValu confirmed its advice for customers to check their bank accounts in an update to its official Northern Ireland profile on Tuesday. However, the supermarket chain has yet to answer numerous questions, including identifying what systems were targeted or the attack vector. It has said "all" customers were affected, so we know at least that the issue isn't restricted to either online or in-store customers alone.

Irish broadcaster RTE reports that "malicious software was discovered in a centralised IT system".

Neither Musgrave nor SuperValu had responded to requests for comment from El Reg at the time of publication. We'll update this story as more information comes to hand. ®