The use of virus-like code that is geared to patching security holes on vulnerable systems has received the thumbs down by members of the security community.
In the wake of the widespread (though at times exaggerated) impact of the Code Red worm and its variants, white hat hackers have posted programs on the net which repairs systems and guards against further infection.
CodeGreen, which was written by Herbert HexXer, goes as far as downloading and installing patches from Microsoft on vulnerable systems. Crclean works in a similar way to Code Green but only spreads itself onto servers which scan a box onto which it has been installed.
The idea of "fighting fire with fire" in this way was used before by the Cheese worm, which fixed a flaw exploited by the Li0n worm on vulnerable Linux boxes.
Alex Shipp, senior antivirus technologist at MessageLabs, which scans its users email for viruses, said whatever the intent behind programs like Code Green they performed unauthorised changes on a network, which could cause serious problems.
Updating systems can go wrong and cause more damage than gets fixed.
Programs similar to Code Green might actually create other security holes, said Shipp, who added the best route was for sys admins to organise a security audit on their own machines. ®