MyTob

Mytob is a quite dangerous mass-mailing worm that uses its own SMTP engine to send an email to addresses that it gathers from the infected computer. The worm composes connected and meaningful messages, attaches infected files and sends them to e-mail addresses, gathered from local files and accounts. It blocks access to security-related web sites and terminates running security software.

The subject of the infected mail will be any one of the following:

(Blank Subject)
hi
hello
status
test
Mail Transaction Failed
error
SERVER REPORT
Mail Delivery System
(Random Characters)