Thousands of SingHealth's front-line computers had exposed its system to hackers' infiltration due to their connectivity to the Internet, said Deputy Prime Minister Teo Chee Hean on 24 July.
Speaking at the Public Service Engineering Conference 2018 at Resorts World Sentosa yesterday, Mr Teo said: "The front-end computers continued to be connected to the Internet. This provided intruders with an attack surface of many thousands of users in the medical and academic community."
"We could and should have implemented Internet surfing separation on public healthcare systems just as we have done on our public sector systems," he noted, higlighting the importance of de-linking computers containing sensitive data from the Internet and stating that the SingHealth breach "could have and would have" been prevented otherwise.
Adding to the above statement, Mr Teo, who is also the coordinating minister for national security, said: "This would have disrupted the cyber kill-chain for the hacker and reduced the surface area exposed to attack."
Consequently, he said that the de-linking of computers in the public healthcare clusters from the Internet has already been done.
He also noted that the stolen data was "exfiltrated to external servers outside Singapore".
However, the authorities have yet to identify the suspects.
"This case reinforces the importance of reporting any intrusion promptly to the Cyber Security Agency of Singapore (CSA)," he stressed.
He also highlighted the significant role of "system logs such as those in the IT system which allowed investigations and diagnoses" in the effort to "contain the intrusion, identify the mode of intrusion, the attack vector, and scope out the extent of damage."
Mr Teo also advised engineers at the seminar to treat cybersecurity "very seriously" and to be prepared to promptly face such cyberattacks, and on a larger scale, the rapid evolution of interconnectivity within and among digital systems on a global level.
He cited as an example that the Government had detected an almost tenfold increase in phishing attacks in Singapore since 2016.
"We need to design our systems and operate them to keep out an attack; detect any intrusions which may have slipped through; respond and deal quickly with such intrusions," said Mr Teo, who stressed that the attack on SingHealth should not deter Singapore from its ambitions to build a Smart Nation.
He acknowledged, however, that technical solutions were not enough in dealing with the recent breach, and that the Government would have to explain the incident to the public and address their concerns "as transparently as possible".
"That is why we are taking the matter very seriously, and have appointed a Committee of Inquiry to look thoroughly into all these aspects, and how we can do better," said Mr Teo.