Hackers had attempted to bring down government websites on Tuesday - the day they urged Singaporeans to mount a protest against the Government's new website licensing rules.
The Infocomm Development Authority (IDA) disclosed this yesterday, after a page on the Istana website was hacked at 12.20am yesterday, an hour after a similar attack on a webpage of the Prime Minister's Office (PMO) site.
Yesterday's intrusions - the first since hackers threatened to hit out at Singapore's infrastructure last week - did not compromise the integrity of the sites in any way, said IDA assistant chief executive James Kang at a media conference.
But in the Tuesday attempt, many government websites - including transactional ones - encountered unusual "spikes" in traffic throughout the day as hackers sought to bring them down through "distributed denial of service attacks (DDoS)", said Mr Kang.
DDoS is a technique used to take down a site by overwhelming it with huge amounts of Internet traffic. But they were unsuccessful and the only mischief they managed was with the affected pages yesterday.
"Data was not compromised, the site was not down and users were not affected," said Mr Kang.
The hacker, or hackers, used a technique called "cross site scripting (XSS)" and exploited a vulnerability in the embedded Google search bar which helps users to search for items within the site.
The attacks were designed to make the webpages look like the hackers had gained access into the sites when they had merely overlaid images over the webpages.
"We detected the exploits within 15 minutes and disabled the search bars within the hour," added Mr Kang.