Despite the arrest Friday of the suspected author of the Sasser worm which affected millions of computers worldwide last week, a new variant of the worm appeared Sunday, according to computer security organizations.

This shows that there is an "organized group of delinquents" engaged in creating and distributing these worms, security specialist Panda Software SL's PandaLabs unit said in a statement.

The Sasser.E worm exploits the same Microsoft Windows LSASS vulnerability targeted by its predecessors and has already infected millions of computers, according to PandaLabs. The situation is likely to get worse when company staff return to work after the weekend, PandaLabs said in its statement.

Sasser.E searches the Internet for vulnerable computers and then copies itself to the Windows directory, leading to a systems error which forces the infected computer to reboot every 60 seconds.

Security company McAfee rated the worm low risk, but noted that it attempts to confuse people trying to remove it by adopting a file named (lsasss.exe) which is very similar to a genuine filename present on most systems.

The same patch which protected against earlier versions of Sasser are also effective against Sasser.E, security experts said.

The Sasser.E worm also tries to remove any instances of the Bagle worm from users' computers, suggesting that there is some rivalry between the virus-writing gangs, according to Panda Labs.

"This seems to indicate that there is a kind of cyber-war being waged among the creators of the Bagle, Mydoom, Netsky and Sasser worms, and it will continue to cause many more variants of the virus," Panda Labs said in its statement.

The IDG News Service is a Network World affiliate.