http://upx.sourceforge.net

Usando su propio SMTP (Simple Mail Transfer Protocol) se auto-envía a las direcciones de correo contenidas en la Libreta de Direcciones de Windows (WAB), carpeta Temporal de Internet o de los archivos con las siguientes extensiones:

• wab
• pl
• adb
• tbb
• dbx
• asp
• edm
• vbs
• wml
• js
• tpl
• conf
• vb
• csp
• asm
• asc
• asa
• dwt
• lbi
• rdf
• rss
• xst
• dlt
• xml
• jsp
• inc
• ssi
• stm
• xht
• htc
• hta
• cgi
• php
• sht
• htm
• txt

Remitente, emplea la técnica Email spoofing que usa aleatoriamente los buzones extraídos del sistema o de los archivos detallados anteriormente.

Asunto, aleatoriamente uno de los siguientes:

• Good day
• Do not reply to this email
• hello
• Mail Delivery System
• Attention!!!
• Mail Transaction Failed
• Server Report
• Status
• Error

Contenido, uno de los siguientes:

• Mail transaction failed. Partial message is available.
• The message contains Unicode characters and has been sent as a binary attachment.
• The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.
• Do not visit these sites!!!
• You have visited illegal websites. I have a big list of the websites you surfed.
• You think it's funny? You are stupid idiot!!! I'll send the attachment to your ISP and then I'll be watching
  how you will go to jail, punk!!!
• Your credit card was charged for $500 USD. For additional in formation see the attachment
• ESMTP [Secure Mail System #334]: Secure message is attached.
• Encrypted message is available.
• Delivered message is attached.
• Can you confirm it?
• Binary message is available.
• am shocked about your document!
• Are you a spammer? (I found your email on a spammer website!?!
• Bad Gateway: The message has been attached.
• Attention! New self-spreading virus!
• Be careful, a new self-spreading virus called "RTSW.Smash" spreading very fast via e-mail and P2P networks. It's about two million people infected and it will be more. to avoid your infection by this virus and to stop it we provide you with full information how to protect yourself
  against it and also including free remover. Your can find it in the attachment.
  2004 Networks Associates Technology, Inc. All Rights Reserved
• New terms and conditions for credit card holders
  Here a new terms and conditions for credit card holders using a
  credit cards for making purchase in the Internet in the attachment.
  Please, read it carefully. If you are not agree with new terms
  and conditions do not use your credit card in the World Wide Web.
  Thank you,
  The World Bank Group
  2004 The World Bank Group, All Rights Reserved
• Thank you for registering at WORLDXXXPASS.COM
  All your payment info, login and password you can find in the
  attachment file. It's a real good choise to go to
  WORLDXXXPASS.COM
• Attention! Your IP was logged by The Internet Fraud Complaint Center
  Your IP was logged by The Internet Fraud Complaint Center. There was
  a fraud attempt logged by The Internet Fraud Complaint Center from
  your IP. This is a serious crime, so all records was sent to the FBI.
  All information you can find in the attachment. Your IP was flagged
  and if there will be anover attemption you will be busted.
  This message is brought to you by the Federal Bureau of Investigation
  and the National White Collar Crime Center
• Here is your documents you are requested.

Anexado, uno de los siguientes:

• document
  readme
  doc
  rules
  file
  data
  docs
  message
  body

Con una de las siguientes extensiones:

• bat
• cmd
• exe
• pif
• scr
• zip

se copia a la carpeta %System% con el nombre de lsasrv.exe y para ejecutarse la próxima vez que se re-inicie el sistema crea y modifica las llaves de registro:

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run]
"lsass" = "%System%\lsasrv.exe"

en Windows 2000/XP modifica el vínculo Explorer shell a:

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon]
"Shellexplorer = "%System%\lsasrv.exe" 

%System% es la variable C:\Windows\System para Windows 95/98/Me, C:\Winnt\System32 para Windows NT/2000 y C:\Windows\System32 para Windows XP y Windows Server 2003.