A report from KnowBe4 in March said the greatest threat now is not payment data but rather the theft of personal information that it describes as “credential harvesting.” This type of stolen credentials has become more popular because the information gives hackers immediate access to personal accounts, allowing them to bypass security measures.

Fashion brand The North Face and luxury jeweller Cartier have become the latest retailers to report having customer data stolen in cyber attacks. North Face has emailed some customers saying it discovered a "small-scale" attack in April this year.

These incidents heighten concerns over the security of consumer information as attackers target high-profile brands.