Luas operators say no financial information has been compromised after its website was hacked overnight.
Anyone going onto the website this morning was greeted with a message describing the attack, with the tram operator being held to ransom for one Bitcoin.
It's claimed the hacker emailed the company some time ago saying that there was security holes, with no reply.
The attacker threatened to 'publish all data and send emails to users' if they refuse to pay one Bitcoin within 5 days - that's around €3,400.
A team of engineers has taken the website offline completely as they look into the issue.
The #Luas website is down at the moment. We will be using this forum only for travel updates should the need arise. We have technicians working on this issue. NF
— Luas (@Luas) January 3, 2019
Luas operatoers Transdev said in a statement; 'The Luas website was compromised this morning , and a malicious message was put on the home page.
It's said that no financial information has been compromised in this attack.
Transdev says that it has identified 3,226 user records which may have been compromised.
These are the records of where people signed up to a Luas Newsletter, and they will be contacted within the next 24 hours.
It's not yet known when the website will be fully restored, but a temporary site will be up and running as soon as possible.
Customers can also contact Luas Customer on 1850 300 604 and firstname.lastname@example.org