State-owned telecom operator BSNL on Thursday said it has advised broadband users to change the default system password after a section of its broadband system was hit by a malware attack earlier this week.

The malware attack impacted nearly 2,000 broadband modems, where subscribers had not changed default password "admin".

"The situation has been addressed to a great extent. We are advising customers that they should immediately change their passwords, and they should not be worried about using broadband once they have done that," BSNL Chairman Anupam Shrivastava told PTI.

He said that the malware has not impacted BSNL's core network, billing or any other system.

Shrivastava said that during the attack, malware was changing the passwords of users (those who were using admin as password) and so the affected modems were unable to login.

This attack occurred earlier this week, he said, adding BSNL call centres were proactively reaching out to users to alert them, and advise them about precautionary measures.