Email-Worm.Win32.Gokar

Class Email-Worm
Platform Win32
Description

Technical Details

This is a virus-worm that spreads via the Internet attached to infected e-mails, and sends itself via IRC channels and infects a IIS server. It also protects itself from anti-virus programs.

The worm itself is a Windows PE EXE file, 14336 bytes in length, and is written in Visual Basic 6. It is packed in a UPX program. After unpacking, it is 53 Kb size. It contains the following text strings:

    W32.Karen by Gobo … happy birthday girl !!! shouts : W1z, Merl, NM, and whoever else.
    #teamvirus on Undernet … say hello. bob is the king of bots 🙂

Infected messages contain the following:

Subject is one from the 15 variants:

  • If I were God and didn’t belive in myself would it be blasphemy
  • The A-Team VS KnightRider … who would win ?
  • Just one kiss, will make it better. just one kiss, and we will be alright.
  • I can’t help this longing, comfort me.
    Li>And I miss you most of all, my darling …

  • … When autumn leaves start to fall
  • It’s dark in here, you can feel it all around. The underground.
  • I will always be with you sometimes black sometimes white …
  • .. and there’s no need to be scared, you re always on my mind.
  • You just take a giant step, one step higher.
  • The air will hold you if you try, trust my wings of desire. Glory, Glorified…….
  • The horizons lean forward, offering us space to place new steps of change.
  • I like this calm, moments before the storm
    Darling, when did you fall..when was it over ?

  • Will you meet me …. and we’ll fly away ?!

Attach file name is random. It has one from the following extensions:
.exe, .pif, .scr, .bat, .com

Sample names are as follows:


3tgf3tgf3tgf373774285313tgf.scr
ffdasfffdasfffdasf145361008658ffdasf.com
rewfdrewfdrewfd30741913208rewfd.scr

The message body is one the following 4 variants:

Hey

  • They say love is blind … well, the attachment probably proves it. Pretty good either way though, isn’t it ?

  • You should like this, it could have been made for you speak to you later

  • Happy Birthday
    Yeah ok, so it’s not yours it’s mine 🙂
    still cause for a celebration though, check out the details I attached

  • This made me laugh
    Got some more stuff to tell you later but I can’t stop right now so I’ll email you later or give you a ring if thats ok ?!
    Speak to you later

Installation

While installing, the worm copies itself to Windows system directory with the name KAREN.EXE and registers that file in system registry auto-run key.

HKLMSoftwareMicrosoftWindowsCurrentVersionRun
Karen = karen.exe

Spreading via E-mail

To send infected messages, the worm uses MS Outlook and sends messages to all addresses found in the Outlook address book.

Gokar1.bmp


Spreading via IRC channels

The worm overwrites the file C:MIRCSCRIPT.INI to the new script file.

This script sends an EXE file to each user joining the infected channel. It also sends the following message:


If this doesn’t make you smile, nothing will.

It changes a user’s nickname to the following:


karen, worm, virus, sex

The script ignores users that send the texts::

script, infected, dcc, script, infected

It joins the channel #teamvirus if it recives a text with char ‘e’.


Infecting IIS server

The worm overwrites the file C:INETPUBWWWROOTDEFAULT.HTM with its code, and copies itself to the directory C:INETPUBWWWROOT with the name WEB.EXE. The new DEFAULT.HTM contains a link to the file WEB.EXE.
It also has a text comment:

As a result, the local IIS server is infected by the worm.

Protecting from anti-viral programs

While installing in the computer system, the worm scans the running processes. It checks their names from the following list:

:


VSHWIN32.EXE
PW32.EXE
_avpm.exe
avpm.exe
ICLOAD95.EXE
ICMON.EXE
IOMon98.exe
VetTray.exe
Claw95.exe

f-stopw.exe

The worm terminates these processes in memory.