THE Central Applications Office (CAO) website yesterday came under attack from cyber hackers for the second time in three days.
The latest incident triggered the automatic issuing of 22,000 new passwords to applicants.
It also led the CAO to shut down parts of the website during the day as engineers sought to find out the extent of the damage.
The attack is the third in less than two months. It caused confusion for some students, especially those on holidays abroad.
But the CAO reassured them the new passwords were genuine and that applicants' data had not been accessed during the attack.
At 9.30 yesterday morning, the CAO technical team disabled the 'Forgot Password' facility as new passwords were being issued by the system to 22,000 applicants by email.
An hour and a half later, the team shut down the interactive 'My Application' section.
"The system was closed for four hours until 3pm while our IT team assessed the site," CAO operations manager Joseph O'Grady told the Irish Independent.
"Again, we apologise sincerely to anyone who was inconvenienced and thank them for their patience and understanding as we manage these malicious attacks."
Mr O'Grady assured applicants that none of their accounts were accessed.
He insisted the new passwords are safe and secure and should be used until further notice. The 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," Mr O'Grady added.
The latest attack prompted a prepared 'script' to issue the new passwords to students by email.
Mr O'Grady said acceptances could also be made by post. "There is plenty of time for applicants to accept their offer: the deadline for acceptances is Monday, August 30 at 5.15pm.
"Those concerned should call our information line on 091-509800 or email us from www.cao.ie," he said.
The CAO has still not decided to call in gardai to investigate the attacks, partly because it is concentrating on getting the second round of college offers out next week. It is also trying to ascertain what exactly happened.
"We are working with our service provider and will engage with consultants and the relevant authorities in the coming days.
"In the meantime, our team will continue to monitor and prevent losses of service on the site," added Mr O'Grady.
Despite the disruption, students are still able to accept offers online. Since 6am on Monday, 26,891 acceptances have been made online.
NUI Maynooth assistant registrar John McGinnity said the attacks had little effect on acceptances for Maynooth, which were up on this time last year.