Worm:W32/NetSky.AB

Classification

Malware

Email-Worm

W32

NetSky.AB, W32/NetSky.AB@mm

Summary

NetSky.AB worm was found on April 28th, 2004. This variant shares nearly 98% of its functionality with NetSky.AA.

Automatic action

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

Suspect a file is incorrectly detected (a False Positive)?

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest detection database updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    NOTE If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note You need administrative rights to change the settings.

For more Support

Community

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User Guide

See the user guide for your product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

Technical Details

The worm's file is a packed PE executable 17920 bytes long.

Installation to system

Upon execution NetSky.AB copies itself as 'csrss.exe' file to Windows folder and adds a startup key for this file into System Registry:

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"BagleAV" = "%WinDir%\csrss.exe"

where %WinDir% represents Windows folder name.

Email Spreading

The worm scans all hard drives from C: to Z: to harvest email addresses. The worm looks for email addresses in files with the following extensions:

.eml
.txt
.php
.cfg
.mbx
.mdx
.asp
.wab
.doc
.vbs
.rtf
.uin
.shtm
.cgi
.dhtm
.adb
.tbb
.dbx
.pl
.htm
.html
.sht
.oft
.msg
.ods
.stm
.xls
.jsp
.wsh
.xml
.mht
.mmf
.nch
.ppt

Netsky.AB worm ignores email addresses that contain any of the following strings:

icrosoft
antivi
ymantec
spam
avp
f-secur
itdefender
orman
cafee
aspersky
f-pro
orton
fbi
abuse
messagelabs
skynet
andasoftwa
freeav
sophos
antivir
iruslis

The worm composes emails with different subject and body texts. Here is the list of subject texts that the worm uses:

Correction
Hurts
Privacy
Password
Criminal
Pictures
Text
Money
Stolen
Found
Numbers
Funny
Only love?
More samples
Picture
Letter
Question
Illegal

The worm uses one of the following text strings as body text for an infected message:

Please use the font arial!
How can I help you?
Still?
I've your password. Take it easy!
Why do you show your body?
Hey, are you criminal?
Your pictures are good!
The text you sent to me is not so good!
True love letter?
Do you have no money?
Do you have asked me?
I've found your creditcard. Check the data!
Are your numbers correct?
You have no chance...
Wow! Why are you so shy?
Do you have more samples?
Do you have more photos about you?
Do you have written the letter?
Does it hurt you?
Please do not sent me your illegal stuff again!!!

Netsky.AB attaches its executable file to emails that it sends out. The attachment name is selected from the following variants:

corrected_doc.pif
hurts.pif
document1.pif
passwords02.pif
image034.pif
myabuselist.pif
your_picture01.pif
your_text01.pif
your_letter.pif
your_bill.pif
my_stolen_document.pif
visa_data.pif
pin_tel.pif
your_text.pif
loveletter02.pif
all_pictures.pif
your_letter_03.pif
your_picture.pif
abuses.pif