Worm.Win32.Collo or Collo (Also known as Email-Worm) is an email worm thought to be from Germany. Aside from some its behavior and its alleged place of origin (though even this is largely speculation, only because its email can come in English and German) little information is available about it.
Collo arrives in an email, which may be in English or German. The English email has a subject line of "Check out this cool program!" and the attachment is "Cool Program.exe". The message is:
I'm writing you this e-mail because I just found out about a very cool program that you need to see. Go check it out yourself, you will love it. Bye bye, your old Friend Energy
The German version is almost completely identical to the English (almost word-for-word). The subject is "Wow dieses Coole Programm!", the attachment is "Wow dieses Coole Programm"
Ich schreib Dir diese e-mail, weil ich dieses Ober Coole Programm gefunden habe. Schau es Dir am besten selbst mal an, Du wirst es Lieben. Tschau, Dein alter Kumpel Energy
It executes the following programs:
ThreatExpert, Worm.Win32.Collo.a. 2007.02.13