The US Computer Emergency Response Team (US-CERT) has issued an alert to users and administrators following the continued spread of attacks which pose as official notifications from government agencies.
The team said that the malware serves victims with alerts claiming to be from the FBI and the US Cyber Command (USCYBERCOM.) The messages demand payment from targets in order to disable system blocks.
According to US-CERT, the malware infection claims that the user's computer has been identified by authorities as having been involved in criminal activities. Users are told that in order to regain use of their systems, a "fine" must be paid to the attacker's account through an online payment service.
The group is warning users not to pay fines which originate from unsolicited messages or notifications. US-CERT also recommends that those who believe they have fallen victim to the attack should report the incident to the FBI.
The alert follows the discovery earlier this month of a malware infection known as Reveton which has been using threats of FBI fines and other tactics to extort users into paying hundreds of dollars to the malware operators.
The claim to government authority has long been a favourite trick among malware writers and online scammers. Typically, attackers have used the lure of phoney tax notifications to trick users into making payments and handing over account details.
Security experts and government agencies alike have pointed out that such official notifications are not sent out as unsolicited emails or alerts and are required to be delivered directly to the individual by law enforcement.