Hackers who accessed the personal particulars and medication data of Prime Minister Lee Hsien Loong were likely trying to obtain what they hoped would be sensitive information to use against him, political and cyber-security experts said.

Dr Shashi Jayakumar, head of the S. Rajaratnam School of International Studies’ (RSIS) Centre of Excellence for National Security, said there was a strong possibility that the cyber attack was state sponsored, given that the Government said it was “targeted”, “carefully planned” and “not the work of casual hackers or criminal gangs”.

“Some states are certainly very capable in this regard,” he said, adding that it could also be a “state actor working in concert with a criminal enterprise, both with their own aims in mind”.

On who the attackers could be, Mr Benjamin Ang of RSIS said it might be “any state who wishes ill of Singapore, or wants an advantage over Singapore, or just wants to collect sensitive information that could be useful one day”.

Mr Ang, who leads the Cyber and Homeland Defence Programme at the Centre of Excellence for National Security, said personal information of high-ranking government officials would be interesting to other states and criminals who could sell it to other countries.

Some information could be sensitive or potentially embarrassing or harmful to confidence, he added. For instance, if attackers discover a previously unknown medical condition, they could use the information to blackmail the Prime Minister or reveal the information to dent Singaporeans’ confidence in him, he said.