Worm.Win32.Shorm

Class Worm
Platform Win32
Description

Technical Details

This is a network worm spreading over local and global networks. To spread, the worm connects to remote computers, and if the disk is shared for full access, the worm copies itself there to the Windows startup directory (if it exists).

The worm also has password stealing ability. It obtains RAS information (user mame, phone numbers, passwords), as well as cached passwords and sends them to two e-mail the addresses of krenx@mail.ru and winam@mail.ru.

The worm itself is a Win32 application (PE EXE file) written in Delphi and compressed with ASpach PE EXE compression utility. The worm body contains the following text:

SharedWorm v1.2

When the worm is run, it copies itself to the Windows system directory using three names: MSTASK.EXE, MSGSRV16.EXE, TAPI32.EXE, and registers these files in the following Registry auto-run keys:

HKCU\SOFTWAREMicrosoftWindowsCurrentVersionRun
HKLM\SOFTWAREMicrosoftWindowsCurrentVersionRun
HKLM\SOFTWAREMicrosoftWindowsCurrentVersionRunServices

So, the worm is run each time Windows is restarted.

The worm then connects to Web page “http://krenx.newmail.ru/ip.txt”, and reads its contents. That page contains a list of subnet IP addresses.
There are three numbers in the address instead of four IP address numbers, for example:

194.135.175.
213.24.179.
195.209.191.
213.59.57.

The worm then randomly selects one of these subnet “masks”, and tries to connect to each machine in the subnet. If connection succeeds, the worm tries to access that computer hard drive disk files, then locates the name of the Windows directory on that computer and copies itself to there with the following name:

Start MenuProgramsStartUpAVPMonitor.exe

So, the worm copy is placed to the Windows auti-start directory, and is activated upon the next Windows restart.

The worm also is able to update itself from an Internet site. It obtains the Internet file “http://krenx.newmail.ru/win.exe”, copies it to the local machine and runs it.