Malaysia’s largest telecommunications company, Telekom Malaysia, suffered a major data breach that compromised the sensitive personal information of users of its high-speed broadband service UNIFI.

Unifi is a high-speed broadband service offered by Telekom Malaysia as a combination of Internet, VoIP and IPTV to residential and business customers in Malaysia through an optical fiber network. The service was launched in 2010 and amassed nearly 3 million subscribers by 2015.

Telekom Malaysia said in a data breach incident notification that it was recently a victim of a significant data breach that compromised the personal data of UNIFI customers. The compromised information included subscribers’ names, national identification details, passport numbers, and contact details.

The company has confirmed that no financial information was accessed by the threat actors.

Though the telecom giant has divulged little about the data breach, it said the incident has been reported to all the relevant authorities, including the National Cyber Coordination & Command Centre (NC4), the Department of Privacy & Data Protection (JPDP), & the Malaysian Communications & Multimedia Commission (MCMC).

“The company confirms that the breach has been contained and proactive steps have been taken to protect the data across its platforms. It has sent out notifications to customers informing them of the data breach and to be wary of phishing tactics including online scams, suspicious links and unsolicited phone calls,” it said. “TM assures all its customers that its Unifi services remain fully operational with no impact to its users.”

According to local media, Telekom Malaysia has already notified all affected Unifi customers via text messages that the company suffered a cyber security incident.  It told affected customers that the affected systems were already isolated and that it has implemented additional security measures to safeguard its customers’ information and is working with relevant authorities for further actions.

TM has urged all Unifi customers to be vigilant about unsolicited messages and phone calls and avoid clicking on any links or downloading attachments from unsolicited emails and text messages.

This is the second cyber security incident Telekom Malaysia suffered in less than a year. In December last year, the company said in a security incident notification that it suffered a data breach that compromised a limited amount of Unifi Mobile customers’ information.

“After investigations, TM has found 250,248 Unifi Mobile customers to be affected in this data breach, constituting both individual customers as well as SMEs. The type of data that was breached involved customer names, phone numbers and emails. No other information was breached.

“TM is closely monitoring the situation and is conducting additional assessments. We advise customers to take extra precautions when receiving communications from unknown parties, as well as to secure their online information at all times,” the company said.