The Central Applications Office website is now fully accessible after the 'my application' section was shut down for four hours today.
CAO Operations Manager Joseph O'Grady said the system was closed down because of a malicious attack on the password facility by 'an unknown source'.
Mr O'Grady said: 'The system was closed for four hours until 3pm while our IT team assessed the site.
'Again, we apologise sincerely to anyone who was inconvenienced and thank them for their patience and understanding as we manage these malicious attacks.
'However, we would like to reassure applicants that no application accounts were accessed and that the new passwords received from the CAO today are safe and secure and should be used until further notice. CAO will email all applicants new passwords and an update today.
'We closed down the interactive part of the website to investigate what happened, and at this stage, we do not believe that applicant accounts have been accessed or that any data has been changed.
'It may not be possible to tell exactly where the attack or attacks are coming from as false internet protocol (IP) addresses are routinely used in such attacks.'
He said students can also post their acceptances to the CAO.
The deadline for accepting first round offers is 30 August at 5.15pm.
Mr O'Grady said that 26,891 acceptances have been made online since Monday morning.
