!rant

This is fucking how you do it!

Ticketmaster UK had a "data security incident" where they don't really know if any data was actually leaked/stolen/"accessed by an unknown third-party" — their response:

1. Disable the compromised service across their platforms
2. Send a mail to any customer that may have been affected (I got one in Danish because I had only interacted with them through a Danish subsidiary)
2b. All notified customers have their passwords reset and must go through the "Forgot password" process; the _temporary_ password they sent me was even pretty nicely random looking: ";~e&+oVX1RQOA`BNe4"
3. Do forensics and security reviews to understand how the data was compromised
3b. Take contact to relevant authorities, credit card companies, and banks
4. Establish a dedicated website (https://security.ticketmaster.co.uk/...) to explain the incident and answer customer questions
5. "We are offering impacted customers a free 12 month identity monitoring service with a leading provider. To request this service please visit [this page]"

EDIT: As mentioned and sourced in the first comment, the breach was apparently noticed by a banking provider and reported to Ticketmaster on the 12th of April and later to Mastercard on the 19th of April.
Ticketmaster's internal investigation found no evidence of breach (which makes sense, as it wasn't an internal breach), but when Mastercard issued an alert to banks about it on the 21st of June, Ticketmaster followed up by finding the actual breach and disabling the breached third party service on the 23rd of June.

I still think they did the right thing in the right way...