Threat Description

NetSky.A

Details

Aliases: NetSky.A, I-Worm.Moodown, W32/Netsky.A@mm, Moodown
Category: Malware
Type:
Platform: W32

Summary



Moodown worm was found on 16th of February 2004. Initially it was sent out in numerous seed e-mails. The worm spreads itself in e-mails inside a ZIP archive or as an executable attachment. It also copies itself to shared folders of all available drives. This allows the worm to spread in P2P (peer-to-peer) and local networks.



Removal



Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.

Eliminating a Local Network Outbreak

If the infection is in a local network, please follow the instructions on this webpage:



Technical Details



Installation to system

When the worm's file is run, it first shows a fake error messagebox:

 Error

 The file could not be opened!

Then the worm copies itself to Windows directory with SERVICES.EXE name and creates a startup key for this file in System Registry:

 [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
 "service" = "%windir%\services.exe -serv"
 

where %windir% represents Windows directory. At the same time the worm also attempts to delete the following key values:

 [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
 "Taskmon"
 "Explorer"
 "system."
 "KasperskyAv"


 [HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
 "Taskmon"
 "Explorer"


 [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices]
 "system."


 [HKCR\CLSID\{E6FB5E20-DE35-11CF-9C87-00AA005127ED}\InProcServer32]

After that the worm starts looking for e-mail addresses. It scans files with the following extensions on all available drives (c:-z:) except CD-ROM drives:

 .msg
 .oft
 .sht
 .dbx
 .tbb
 .adb
 .doc
 .wab
 .asp
 .uin
 .rtf
 .vbs
 .html
 .htm
 .pl
 .php
 .txt
 .eml

If the worm finds a folder with the 'sharing' or 'share' name, it copies itself to that folder with the following names:

 winxp_crack.exe
 dolly_buster.jpg.pif
 strippoker.exe
 photoshop 9 crack.exe
 matrix.scr
 porno.scr
 angels.pif
 hardcore porn.jpg.exe
 office_crack.exe
 serial.txt.exe
 cool screensaver.scr
 eminem - lick my pussy.mp3.pif
 nero.7.exe
 virii.scr
 e-book.archive.doc.exe
 max payne 2.crack.exe
 how to hack.doc.exe
 programming basics.doc.exe
 e.book.doc.exe
 win longhorn.doc.exe
 dictionary.doc.exe
 rfc compilation.doc.exe
 sex sex sex sex.doc.exe
 doom2.doc.pif

Spreading in e-mails

When Internet connection is available, the worm starts to spread itself. It creates ZIP archives with its file in Windows directory. The names of these ZIP archives are the same as the names of worm's files inside:

 prod_info_04155.bat
 prod_info_54234.scr
 prod_info_42313.pif
 prod_info_33462.cmd
 prod_info_49541.exe
 prod_info_04650.bat
 prod_info_54739.scr
 prod_info_42818.pif
 prod_info_33967.cmd
 prod_info_49146.exe
 prod_info_54235.scr
 prod_info_42314.pif
 prod_info_54433.doc.exe
 prod_info_47532.doc.scr
 prod_info_43631.doc.exe
 prod_info_56780.doc.exe
 prod_info_43859.htm.scr
 prod_info_87968.htm.scr
 prod_info_34157.htm.exe
 prod_info_77256.txt.scr
 prod_info_33325.txt.exe
 prod_info_56474.txt.exe
 prod_info_33543.rtf.scr
 prod_info_65642.rtf.scr
 prod_info_55761.rtf.exe

The worm spreads itself in e-mails as a ZIP attachment or as an attachment with one of the above shown names. The infected e-mails sent by the worm look like that:

From:

 EBay Auctions <responder@ebay.com>

or

 Yahoo Auctions <auctions@yahoo.com>
 
 

or

Amazon automail <responder@amazon.com>

or

MSN Auctions <auctions@msn.com>

or

QXL Auctions <responder@qxl.com>

or

Ebay Auctions <responder@ebay.com>


Subject:


 Auction successful!


Body:


 #----------------- message was sent by automail agent ------------------#


 Congratulations!


 You were successful in the auction.


 Auction ID <random number>
 Product ID <random number>


 A detailed description about the product and the bill
 are attached to this mail.
 Please contact the seller immediately
 
 Thank you!

The worm's file is attached to the infected e-mail inside a ZIP archive or as an normal binary file. The following ZIP attachent names are used by the worm:

prod_info_04155.zip
 prod_info_54234.zip
 prod_info_42313.zip
 prod_info_33462.zip
 prod_info_49541.zip
 prod_info_04650.zip
 prod_info_54739.zip
 prod_info_42818.zip
 prod_info_33967.zip
 prod_info_49146.zip
 prod_info_54235.zip
 prod_info_42314.zip
 prod_info_54433.zip
 prod_info_47532.zip
 prod_info_43631.zip
 prod_info_56780.zip
 prod_info_43859.zip
 prod_info_87968.zip
 prod_info_34157.zip
 prod_info_77256.zip
 prod_info_33325.zip
 prod_info_56474.zip
 prod_info_33543.zip
 prod_info_65642.zip
 prod_info_55761.zip

A recipient has to unpack the worm's attachment from a ZIP archive and run it to get infected.






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