Worm:W32/Gurong.A

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Classification

Category:

Malware

Type:

Email-Worm

Platform:

W32

Aliases:

Email-Worm.Win32.Gurong.a

Summary

Worm:W32/Gurong.A worm in emails and in Kazaa shared folders. It has a rootkit functionality.This worm appeared on the 21st of March 2006.

Removal

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.

Find out more

Knowledge Base

Find the latest advice in our Community Knowledge Base.

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

Installation

After the worm's file is run, it copies itself to the Windows System folder as wmedia16.exe and creates a startup key value for this file in the registry.

Rootkit

The worm is able to hide the following items:

Processes
Files
Registry keys and values

When the worm is active, it hides its own process, file and launch point in the registry.The worm installs a call gate through \Device\PhysicalMemory to execute part of its code in kernel mode (ring 0). The kernel-mode code replaces the following function pointers from the system service table:

NtClose
NtCreateFile
NtEnumerateKey
NtEnumerateValueKey
NtOpenFile
NtQueryDirectoryFile

This allows it to hide files, registry keys and values. In addition, the worm is able to modify kernel-mode process structures to hide any process it specifies.

Propagation (email)

Before spreading, the worm looks for email addresses in the victim's Windows Address Book (WAB) file and also in files with the following extensions:

The worm ignores email addresses that contains any of the following substrings:

.aero
.gov
.mil
accoun
AccountRobot
acketst
admin
alert
anyone
arin.
avp
berkeley
borlan
bsd
bsd
bugs
ca
certific
contact
example
feste
fethard
fido
foo.
fraud
fsf.
gnu
gold-certs
google
google
gov.
help
hotmail
iana
ibm.com
icrosof
icrosoft
ietf
info
inpris
isc.o
isi.e
kernel
linux
linux
listserv
math
me
mit.e
mozilla
msn.
mydomai
no
nobody
nodomai
noone
not
nothing
ntivi
page
panda
pgp
postmaster
privacy
rating
rfc-ed
ripe.
root
ruslis
samples
secur
sendmail
service
site
soft
somebody
someone
sopho
submit
support
syma
tanford.e
the.bat
unix
unix
usenet
utgers.ed
webmaster
webmoney
you
your

The worm then constructs the email message used to deliver the worm's file by using the following "building blocks". The subject of the message can be one of the following:

Greetings!
Hello friend ;)
Hey dear!
Re: Hello
Re: I got it! Try it now!
Re[2]: wazzup bro
Wazzap bro!!

The body text can be one of the following:

Greetings! Check out my portfolio, please! Here is some my photos in the archive.
Greetings. Here is some my nude photos in the attachment.
Hello bro! Here is my new girlfriend's photo! Check it out!
Hello buddy! Take a look at attachment! Here is my nude 17-yr sister!
Hello! Here is NEW smiles pack for MSN messenger! It is really cool ;)
Hello! I sent you new skype plug-in, as you wished.
Hello! There is NEW plug-in for MSN. Try it out!
Hey bro! Check out attachment! There is a new plug-in for skype!
Hey dear! Here is my photos, as I promised.
Hey friend! Try this new smiles pack for MSN messenger!
Hey man! Take a look at attachment!
Whatz up man! There is my nude 17-yr sister in the attachment!'

The infected attachment name can be any of the following:

body
conf_data
doc
document
i_love_u
i_luv_u
port_imgs
sex_girls
sex_pics

Infected attachments can have the following extensions:

The worm spoofs (fakes) the sender's email address. The following user names are used to compose the fake sender's address:

adam
alex
alexey
alice
andrew
anna
bob
boris
brenda
brent
brian
claudia
craig
cyber
dan
dave
david
debby
den
dmitry
frank
george
gerhard
helen
ilya
james
jane
jayson
jerry
jim
jimmy
joe
john
jose
julie
kevin
lee
leo
linda
linda
maria
marina
mary
matt
michael
mike
nikolay
olga
peter
ray
robert
sam
sandra
serg
smith
steve
tom
vlad
vladimir

The following domain names are used to compose the fake sender's address:

aol.com
earthlink.net
hotmail.com
msn.com
yahoo.com

Propagation (File sharing)

The worm copies itself to the shared folder of the peer-to-peer Kazaa client, with the following names:

0day_patch
dcom_patches
icq5
lsas_patches
msblast_patches
office_crack
skype_video
strip-girl4.0c
trillian_crack_all
winamp5
xp_activation

The extensions of the copied files are randomly selected from the following variants:

Registry Modifications

Creates these keys:

[HKLM\Software\Microsoft\Windows\CurrentVersion\Run] "WMedia16" = "%WinSysDir%\wmedia16.exe"