F-Secure Virus Descriptions : NetSky.E

[Summary] | [Disinfection] | [Detailed Description] | [Detection]

NAME:	NetSky.E
ALIAS:	W32/NetSky.E@mm, Somefool, I-Worm.NetSky.e
SIZE:	24840

Summary

NetSky.E (also known as Moodown.E) worm was found on 1st of March 2004 just a few hours after NetSky.D variant. The .E variant is very close to .C variant of the worm. NetSky.E spreads itself in e-mails inside a ZIP archive or as an executable attachment.

Disinfection

F-Secure provides the special disinfection utility to eliminate Netsky.E worm infection. You can download this utility from our ftp site:

ftp://ftp.f-secure.com/anti-virus/tools/f-netsky.exe

ftp://ftp.f-secure.com/anti-virus/tools/f-netsky.zip

Disinfection instructions can be found here:

ftp://ftp.f-secure.com/anti-virus/tools/f-netsky.txt

System administrators who are using F-Secure Policy Manager, can distribute the tool as a JAR package automatically to all workstations.

System administrators can download the JAR version from:

http://www.europe.f-secure.com/tools/f-netsky.jar

ftp://ftp.europe.f-secure.com/anti-virus/tools/f-netsky.jar

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Detailed Description

Descriptions of previous NetSky variants can be found here:

W32/NetSky.A@mm: http://www.f-secure.com/v-descs/moodown.shtml

W32/NetSky.B@mm: http://www.f-secure.com/v-descs/netsky_b.shtml

W32/NetSky.C@mm: http://www.f-secure.com/v-descs/netsky_c.shtml

W32/NetSky.D@mm: http://www.f-secure.com/v-descs/netsky_d.shtml

The differences between NetSky.E variant and the .C variant of the worm are as follows:

1. The worm's file is a PE executable file 24840 bytes long packed with Petite file compressor. The unpacked file's size is over 40 kilobytes.

2. On March 2nd, 2004 the worm constantly beeps with PC speaker from 6:00 to 8:59. Below is the link to the WAV file with the sound that the worm makes:

http://www.f-secure.com/virus-info/v-pics/netsky_d.wav

3. The NetSky.E worm doesn't copy its files to shared folders.

4. The NetSky.E worm variant uses 2 more extensions (.jpg and .gif) for the first extension (if double extension file name is generated) of its attachment:

 .txt
 .rtf
 .doc
 .htm
 .jpg
 .gif

5. The .E worm variant uses 2 more extensions (.bat and .cmd) for the second extension (if double extension file name is generated) or for the only extension of its attachment:

 .exe
 .scr
 .com
 .pif
 .bat
 .cmd

6. The .E worm variant has 2 more strings ('messagelabs' and 'skynet') added to the list of strings that it uses to avoid sending its e-mails to specified e-mail addresses:

 icrosoft
 antivi
 ymantec
 spam
 avp
 f-secur
 itdefender
 orman
 cafee
 aspersky
 f-pro
 orton
 fbi
 abuse
 messagelabs
 skynet

7. This variant has a bigger list of subjects:

 Delivery Failed
 Status
 report
 question
 trust me
 hey
 Re: excuse me
 read it immediatelly
 hi
 Re: does it?
 Yep
 important
 hello
 dear
 Re: unknown
 fake?
 warning
 moin
 what's up?
 info
 Re: information
 Here is it
 stolen
 private?
 good morning
 illegal...
 error
 take it
 re:
 Re: Re: Re: Re:
 you?
 something for you
 exception
 Re: hey
 excuse me
 Re: hi
 Re: does it?
 Re: important
 Re: hello
 believe me
 Question
 denied!
 notification
 Re: <5664ddff?$??�2>
 lol
 last chance!
 I'm back!
 its me
 notice!
 oh
 Announcement
 Re: Thank you
 Re: Details
 Thank you
 Details
 Re: Approved
 Approved
 hi, it's me
 Thank You very very much
 You use illegal...
 Your IP was logged
 Love is
 Re: <censored>
 registered?
 Your request was registered
 read now!
 Attention
 Schedule
 You have 1 day left
 Re: information
 automatic notification
 Expired account
 automatic responder
 Read this message
 please read
 please reply
 Registration confirm
 Confirmation
 Confirmation Required
 Returned Mail

The .E worm variant just like the .C variant spreads itself in e-mails as a ZIP attachment or as an executable attachment with one of the hardcoded names and single or double extension. A recipient has to unpack the worm's attachment from a ZIP archive and to run it or to run an executable attachment to get infected.

Like the .C variant, NetSky.E worm variant installs itself as WINLOGON.EXE file to Windows folder and creates a startup key for this file in the Registry:

 [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
 "ICQ Net" = "%windir%\winlogon.exe -stealth"

where %windir% represents Windows directory.

For more details, please see the description of NetSky.C worm variant.

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Detection

Detection for NetSky.E (Moodown.E) worm is available in the following FSAV updates:

[FSAV_Database_Version]

Version=2004-03-01_05

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Technical Details: Alexey Podrezov, March 1st, 2004;

Description Updated: Alexey Podrezov, March 18th, 2004;

F-Secure Corporation