F-Secure Virus Descriptions : Gop (worm)

NAME:	Gop (worm)
ALIAS:	I-Worm.GOPworm, W32/Invery.A@mm, Invery

Gop is a worm that spreads via the Internet being attached to infected emails and through local network by copying to shared drives. The worm itself is a Windows PE EXE file about 60Kb of length (compressed by UPX), written in Delphi Microsoft Visual C++.

The worm is improved variant of a password stealing trojan Trojan.PSW.GOP (trojan).

The infected messages Subject and Body are in Chinese. The attached file name is different, and has double extension:

 filename.jpg.exe
 filename.jpeg.exe
 filename.gif.exe
 filename.txt.exe
 filename.doc.exe
 filename.rtf.exe
 filename.bmp.exe

To run from infected message the worm uses IFrame security breach.

While installing the worm uses the same way as "GOPtrojan", the additional feature is affected Registry key:

 HKCR\exefile\shell\open\command

To send infected messages the worm uses direct access to a SMTP server. The worm gets victim email addresses by scanning *.HTML, *.HTM, *.JS files, as well as by scanning TheBat, Aerofox and RimArts email databases.

[Analysis: Kaspersky Labs; January 2002]