NetSky.E

Threat description

Details

CATEGORYMalware
TYPEEmail-Worm

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.

Removal

Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More scanning & removal options

More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.

You may also refer to the Knowledge Base on the F-Secure Community site for further assistance.

Eliminating a Local Network Outbreak

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

Technical Details

Descriptions of previous NetSky variants can be found here:

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

  • 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.
  • 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: https://www.f-secure.com/virus-info/v-pics/netsky_d.wav
  • The NetSky.E worm doesn't copy its files to shared folders.
  • 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
    
    
  • 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
    
  • 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
    
  • 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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