The Vietnam Computer Emergency Response Team (VNCERT) has sent a red alert to all computer users to immediately strengthen their antivirus software against Internet worm Conficker which has recently become more virulent.

The Conficker Internet worm has just become more deadly following an upgrade and the Vietnam Computer Emergency Response Team is warning computer users to be wary

VNCERT said starting April 1 the new worm would attack computers around the world connected to the Internet. It first appeared in January but a few days ago appears to undergone an upgrade and can break through some fragile firewalls.
 
The worm enables cybercrime by allowing its creators to remotely install software on infected machines. It creates a botnet - software robots, or bots, that run autonomously and automatically -- that can be rented out to criminals who want to send spam, steal IDs, and direct users to online scams and phishing sites.

The Conficker worm mostly spreads across networks. If it finds a vulnerable computer, it turns off the automatic backup service, deletes previous restore points, disables many security services, blocks access to a number of security websites and opens infected machines to receive additional programs from the malware’s creator.
 
The worm tries to take advantage of a problem with Windows (a vulnerability) called MS08-067 to surreptitiously install itself. Users who automatically receive updates from Microsoft are protected from this. The worm also tries to spread by copying itself into shared folders on networks and by infecting USB devices such as memory sticks.
 
Users whose computers are not configured to receive patches and updates from Microsoft and who are not running an up-to-date antivirus product are most at risk.
 
Conficker, sometimes called the Downadup or Kido worm, has managed to infect a large number of computers. Specifics are hard to come by, but some researchers estimate that millions of computers have been infected since January.