17:24 14 February 2014
Tesco is now investigating how a list of more than 2,000 Tesco.com account details was obtained and posted to a popular text-sharing site.
Meanwhile, the supermarket giant decided to deactivate some customers’ net accounts as a precaution. It also said that the data shared online had been compiled by hackers using details stolen from other sites.
"We have contacted all customers who may have been affected and are committed to ensuring that none of them miss out as a result of this," Tesco said in a statement.
"We will issue replacement vouchers to the very small number who are affected."
Some affected customers were already contacted and some said that attackers had used their accounts to steal store vouchers.
This isn’t the first time that Tesco was victimized by cyber thieves. In early 2013, hundreds of owners of Tesco Clubcards said that their loyalty accounts were hacked as well.