Summary

W32/Buchon@mm worm was found on October 21st, 2004. This variant is probably a hack made in South Korea. It was originally identified as Netsky, but all major Antivirus vendors realized it has not much to do with that family besides some similarities in the emails it sends. Therefore the new name is Buchon.

Additional Details

The worm is packed with an unmodified version of UPX, once unpacked it grows to around 60 KiB This worm contains two hidden strings: "SoonChunHyang" and "Bucheon". There's a University called SoonChunHyang in the city of Bucheon, South Korea. This virus is buggy and fails to replicate properly. Email messages W32/Buchon@mm tries to send can vary a lot. In some cases it sends somewhat personalized messages looking like this:

 
 
  From: randomaddress@somewhere.com
  To: bob@acme.com
  Subject: Mail Delivery failure - bob@acme.com

 
 
  If the message will not displayed automatically,
  . you cancheck original in attached message.txt
  www.acme.com/inbox/security/read.asp?sessionid-5339

 
 
  Attachment: "message.txt                  mcafee.com"

W32/Buchon@mm searches local drives for e-mail addresses. Files with following extensions are scanned for e-mail addresses:

 
 
 .dbx
 .wab
 .mbx
 .eml
 .mdb
 .tbb

The worm also drops a keylogger.

Detection

F-Secure AntiVirus detects W32/Buchon@mm with update 2004-10-21_03. [FSAV_Database_Version] Version=2004-10-21_03

Write-up: Mikko Hypponen, October 21st, 2004. Updated: Ero Carrera, October 22nd, 2004. F-Secure Corporation