The trojan downloader family consists of dozens of different variants.
The main characteristic of these downloaders is that they hiddenly
download and run executable files on a user's computer.
Many of these downloaders are compressed with different file
compressors to reduce their size and to hide their contents from
users' eyes.
These Trojans are typically distributed via email attachments.
This variant was distributed widely in July 2005, as fake bill
from Deutsche Telekom. The filename used was rechnung.pdf.exe.
For the disinfection instructions for this type of malware please refer
to this webpage:
http://www.f-secure.com/v-descs/trojdown.shtml
Writeup:
Mikko Hypponen, July 20th, 2005;
F-Secure Corporation