Three new variants of the Beagle worm (also known as "Bagle") were unleashed last week, according to security vendor Symantec.
The US-based software company said the latest iterations of the mass-mailer worms include W32.Beagle.AV@mm, W32.Beagle..AU@mm and W32.Beagle.AW@mm.
A Symantec security alert said the new Beagle worms spread through file-sharing networks and open a backdoor on TCP port 81. They affect systems running Windows 2000, Windows 95, Windows 98, Windows ME, Windows NT, Windows Server 2003 and Windows XP.
The new Beagles are each Category 3 threat-level viruses, according to Symantec, which has them listed as the current top virus threats.
Complete details and remediation procedures can be found at Symantec's website.