StarHub has confirmed that its broadband disruptions on Saturday and Monday were due to cyber attacks.

In a statement late yesterday, StarHub said that it had suffered "intentional" and "likely malicious" distributed denial-of-service (DDoS) attacks on its Domain Name Servers (DNS). DDoS attacks work by having thousands of infected computers accessing and overwhelming a targeted site, causing a spike in traffic.

Such attacks led to a massive Internet outage on the east coast of the United States last Friday, cutting off access to websites ranging from the New York Times site to Spotify.

On Saturday and Monday, StarHub broadband customers were affected by disruptions lasting about two hours each owing to a spike in traffic to its DNS. "These two recent attacks that we experienced were unprecedented in scale, nature and complexity," the telco said.

On both occasions, it mitigated the attacks by filtering unwanted traffic and increasing its DNS capacity. It maintained that the security of customers' information was not compromised.

The incident took place on the heels of the attacks in the United States targeted at US-based Internet infrastructure provider Dyn, which provides managed DNS services.

A DNS is a database that translates Web addresses such as www.nameofwebsite.com into machine-readable sets of digits - also known as Internet protocol addresses - for customers to view websites on their computers. When a DNS is not operating optimally, customers may not be able to access websites.

Earlier yesterday, the Cyber Security Agency and the Infocomm Media Development Authority urged StarHub to determine the root cause of the problem and prevent a recurrence.

StarHub said it will continue to stay vigilant and is working closely with the authorities to determine the intent and source of the two DDoS attacks.