The advisory also states that individuals or organisations should not pay the ransom, as this does not guarantee that files would be released.
Such instances of fraud should be reported to Indian Computer Emergency Response Team (CERT-In) and law enforcement agencies, an official spokesman said here today.
He said that to prevent ransomware attacks, which spread across networks and hold files to ransom, people should maintain updated antivirus software on all systems.
They should check regularly the integrity of the information stored in the databases and also check the contents of back up files of databases for any unauthorised encrypted contents of data records or external elements, such as backdoors or malicious scripts.
The advisory cautions against opening attachments in unsolicited e-mails, even if they come from people in their contact list.
"People should never click on a URL contained in an unsolicited e-mail, even if the link seems benign. In cases of genuine URLs, close the e-mail and go to the organisation's website directly through browser," the spokesman added.