Disruptions were not due to cyber attack
Insufficient system capacity cause of StarHub's broadband problem last October
StarHub was warned by the authorities yesterday for two disruptions to its home broadband network in October last year.
Investigation findings now show that the disruptions were not due to direct cyber attacks as the telco had suspected.
Findings released yesterday by the Infocomm Media Development Authority (IMDA) and the Cyber Security Agency of Singapore (CSA) showed that StarHub did not have sufficient system capacity to cope with an Internet traffic surge.
They added that the telco has since increased its capacity.
IMDA also directed StarHub to do an independent review of its infrastructure, saying it "will not hesitate to take sterner action should a similar incident happen in future".
IMDA's code spells out the minimum requirements for service availability. Breaching these requirements - such as a loss of 70 per cent or more of a telco's Internet bandwidth - may result in a fine ranging from $15,000 to $270,000 for every 30 minutes of outage.
Subscribers could not surf the Internet intermittently for up to two hours each time on Oct 22 and 24 as traffic spiked on StarHub's DNS, which maps Web addresses to a machine-readable string of numbers to connect users to websites.
When the DNS is not operating optimally, users may not be able to access the websites.
The two disruptions came on the heels of a cyber attack the week before on US-based DNS service provider Dyn.
That was why IMDA and CSA did not rule out the possibility of a cyber attack.
(IMDA) will not hesitate to take sterner action should a similar incident happen in futureIMDA's warning to StarHub
The surge on StarHub's network was indirectly linked to Dyn, said IMDA and CSA.
Affected content providers in the US were routed to a different technology that conducts extra verification checks on traffic, including those from StarHub broadband users.
The extra checks generated more traffic that clogged StarHub's network, resulting in surfing slowdowns.
This could have prompted broadband users here to repeatedly refresh their Web browsers, which added to the jam.
Mr Chong Siew Loong, StarHub's chief technology officer, said: "We assure our customers and the regulator that we will continuously review our security posture and enhance network resilience in partnership with network and security providers."