One of the biggest event booking sites in the world, UK-based Ticketmaster, has been hacked, exposing customer data that includes their payment card details.

Any UK-based customers who used the site book tickets from February 2018 and 23 June 2018 may have lost data that incudes their name, email address, physical address, telephone number, Ticketmaster logins and payment card details.

International customers who used the site between September 2017 and 23 June 2018 could also be affected.

According to Ticketmaster, it identified malicious software on a customer support product hosted by external third-party supplier Inbenta Technologies on Saturday 23 June 23.

The software was disabled, but not before about 5% of Ticketmaster’s global customer base were affected by this incident.

“As a result of Inbenta’s product running on Ticketmaster International websites, some of our customers’ personal or payment information may have been accessed by an unknown third-party,” the company says in a statement.

“We have contacted customers who may have been affected by the security incident.

“If you have not received an email, we do not believe you have been affected by this security incident based on our investigations.

“We recommend that you monitor your account statements for evidence of fraud or identity theft. If you are concerned or notice any suspicious activity on your account, you should contact your bank(s) and any credit card companies.”

Ticketmaster has also advised customers to reset their passwords next time they log into their accounts.

“We are offering impacted customers a free 12-month identity monitoring service with a leading provider,” the company adds.

Paul Ducklin, senior technologist at Sophos, believes Ticketmaster’s woes are just starting.

“Data breaches are bad news at the best of times. But this breach was caused by a third party, and went on apparently unchecked for five months, so the news in this case is even worse: the longer a breach lasts, and the further away from your own control it takes place, the harder it is to get to the bottom of it.

“It’s a bit like taking a closer look at that rust spot on your car that you’ve been ignoring since last year. You might get lucky, but the chances are that you will find more rust … that will lead you to more rust … that will lead you to more rust, and so on, and you’ll never quite have the confidence to pronounce that you’ve found and eliminated it all.”