Threat Description

Email-Worm:​W32/Warezov.U

Details

Aliases:Email-Worm.Win32.Warezov.u
Category:Malware
Type:Email-Worm
Platform:W32

Summary



This type of worm is embedded in an e-mail attachment, and spreads using the infected computer's e-mailing networks.



Removal


Automatic action

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

More

You may wish to refer to the Support Community for further assistance. You also may also refer to General Removal Instructions for a general guide on alternative disinfection actions.



Technical Details



Warezov.U is a mass-mailing worm that sends itself as e-mail attachments to addresses found on the infected computer. Warezov.U also downloads another worm variant from a specified website on the Internet.

Installation

Warezov.U creates a temporary file in the directory from where it was executed using the following filename:

  • %NumTimes%.tmp

Note: %NumTimes% is the number (value is in hexadecimal) of times the malware was executed on the computer system.

This created temporary file contains random characters inside and is displayed using notepad upon execution of the malware. This is used as a decoy to fool the users into thinking that this was the file executed instead of the actual worm. Below is a sample of the displayed notepad window:

In other instances, the worm displays the following message box instead:

During the installation, the following files are added to the system:

  • %SysDir% \cmut449c14b7.dll
  • %SysDir%\ msji449c14b7.dll
  • %SysDir%\hpzl449c14b7.exe
  • %windir%\tsrv.dll - Files also detected as Warezov.U.
  • %windir%\tsrv.exe - A copy of the worm.
  • %windir%\tsrv.s
  • %windir%\tsrv.wax
  • %windir%\tsrv.z - Non-malicious components.

This worm also modifies the host file to prevent access to the following websites (Most are antivirus related):

  • avp.ru
  • avp.ru/download/
  • customer.symantec.com
  • download.microsoft.com
  • downloads1.kaspersky-labs.com
  • downloads1.kaspersky-labs.com/products/
  • downloads1.kaspersky-labs.com/updates/
  • downloads2.kaspersky-labs.com
  • downloads2.kaspersky-labs.com/products/
  • downloads2.kaspersky-labs.com/updates/
  • downloads3.kaspersky-labs.com
  • downloads3.kaspersky-labs.com/products/
  • downloads3.kaspersky-labs.com/updates/
  • downloads4.kaspersky-labs.com
  • downloads4.kaspersky-labs.com/products/
  • downloads4.kaspersky-labs.com/updates/
  • downloads5.kaspersky-labs.com
  • downloads5.kaspersky-labs.com/products/
  • downloads5.kaspersky-labs.com/updates/
  • eset.com/
  • eset.com/download/index.php
  • eset.com/joomla/
  • eset.com/products/index.php
  • ftp://downloads1.kaspersky-labs.com
  • ftp://downloads1.kaspersky-labs.com/products/
  • ftp://downloads1.kaspersky-labs.com/updates/
  • ftp://downloads2.kaspersky-labs.com
  • ftp://downloads2.kaspersky-labs.com/products/
  • ftp://downloads2.kaspersky-labs.com/updates/
  • ftp://downloads3.kaspersky-labs.com
  • ftp://downloads3.kaspersky-labs.com/products/
  • ftp://downloads3.kaspersky-labs.com/updates/
  • ftp://downloads4.kaspersky-labs.com
  • ftp://downloads4.kaspersky-labs.com/products/
  • ftp://downloads4.kaspersky-labs.com/updates/
  • ftp://downloads5.kaspersky-labs.com
  • ftp://downloads5.kaspersky-labs.com/products/
  • ftp://downloads5.kaspersky-labs.com/updates/
  • ftp://ftp.kasperskylab.ru/updates/
  • ftp://updates.kaspersky-labs.com/updates/
  • ftp://updates1.kaspersky-labs.com/updates/
  • ftp://updates2.kaspersky-labs.com/updates/
  • ftp://updates3.kaspersky-labs.com/updates/
  • ftp://updates4.kaspersky-labs.com/updates/
  • go.microsoft.com
  • http://avp.ru
  • http://customer.symantec.com
  • http://downloads1.kaspersky-labs.com
  • http://downloads1.kaspersky-labs.com/products/
  • http://downloads1.kaspersky-labs.com/updates/
  • http://downloads2.kaspersky-labs.com
  • http://downloads2.kaspersky-labs.com/products/
  • http://downloads2.kaspersky-labs.com/updates/
  • http://downloads3.kaspersky-labs.com
  • http://downloads3.kaspersky-labs.com/products/
  • http://downloads3.kaspersky-labs.com/updates/
  • http://downloads4.kaspersky-labs.com
  • http://downloads4.kaspersky-labs.com/products/
  • http://downloads4.kaspersky-labs.com/updates/
  • http://downloads5.kaspersky-labs.com
  • http://downloads5.kaspersky-labs.com/products/
  • http://downloads5.kaspersky-labs.com/updates/
  • http://kaspersky.com
  • http://kaspersky.ru
  • http://kaspersky.ru/updates/
  • http://kaspersky-labs.com
  • http://kaspersky-labs.com/updates/
  • http://liveupdate.symantec.com
  • http://liveupdate.symantecliveupdate.com
  • http://securityresponse.symantec.com
  • http://service1.symantec.com
  • http://symantec.com
  • http://symantec.com/updates
  • http://u3.eset.com/
  • http://u4.eset.com/
  • http://updates.kaspersky-labs.com/updates/
  • http://updates.symantec.com
  • http://updates1.kaspersky-labs.com/updates/
  • http://updates2.kaspersky-labs.com/updates/
  • http://updates3.kaspersky-labs.com/updates/
  • http://updates4.kaspersky-labs.com/updates/
  • http://viruslist.com
  • http://viruslist.ru
  • http://www.avp.ru
  • http://www.avp.ru/download/
  • http://www.eset.com/
  • http://www.eset.com/download/index.php
  • http://www.eset.com/joomla/
  • http://www.eset.com/products/index.php
  • http://www.kaspersky.ru/updates/
  • http://www.kaspersky-labs.com/updates/
  • http://www.microsoft.com/downloads/Search.aspx?displayl
  • kaspersky.com
  • kaspersky.ru
  • kaspersky-labs.com
  • liveupdate.symantec.com
  • liveupdate.symantecliveupdate.com
  • msdn.microsoft.com
  • office.microsoft.com
  • securityresponse.symantec.com
  • service1.symantec.com
  • symantec.com
  • symantec.com/updates
  • u3.eset.com/
  • u4.eset.com/
  • updates.symantec.com
  • viruslist.com
  • viruslist.ru
  • windowsupdate.microsoft.com
  • www.avp.ru
  • www.avp.ru/download/
  • www.eset.com/
  • www.eset.com/download/index.php
  • www.eset.com/joomla/
  • www.eset.com/products/index.php
  • www.kaspersky.com
  • www.kaspersky.ru
  • www.kaspersky-labs.com
  • www.symantec.com
  • www.symantec.com/updates
  • www.viruslist.com
  • www.viruslist.ru

It tries to terminate the following services (mostly antivirus related):

  • Agnitum Outpost Firewall
  • Windows Security Center
  • McAfee Personal Firewall
  • Sygate Personal Firewall
  • Symantec Internet Security
  • Kerio WinRoute
  • Zone Labs ZoneAlarm

It also tries to terminate the following processes:

  • ccapp.exe
  • cwsmc.exe
  • explorer.exe
  • firefox.exe
  • iexplore.exe
  • mpftray.exe
  • opera.exe.
  • outpost.exe
  • services.exe
  • svchost.exe
  • vzapro.exe
  • zlclient.exe

Activity

Warezov.U attempts to connect to the following site to download another malware file:

  • http://yuhadefunjinsa.com/chr/grw/[REMOVED].exe

This attempted file download is already detected as Email-Worm.Win32.Warezov.t. The worm uses rootkit features to hide its process in memory.

Propagation

Warerov.U gathers target e-mail addresses from the Windows Address Book (WAB). It may also harvests e-mail addresses from the infected system by scanning through files with the following extension names:

  • asp
  • cfg
  • cgi
  • dbx
  • eml
  • htm
  • htm
  • html
  • jsp
  • mbx
  • mdx
  • mht
  • mmf
  • msg
  • nch
  • ods
  • oft
  • php
  • pl
  • sht
  • shtm
  • stm
  • tbb
  • txt
  • uin
  • wab
  • wsh
  • xls
  • xml

The worm filters found e-mail addresses to avoid sending itself to addresses that contain any of the following substrings:

  • .edu
  • .gov
  • @avp
  • admin
  • anyone@
  • apache
  • berkeley
  • bsd
  • cafee
  • certific
  • contract@
  • example
  • fido
  • ftp
  • gnu
  • gold-certs
  • google
  • help@
  • ibm.com
  • info@
  • kasp
  • kernel
  • linux
  • local
  • master
  • microsoft
  • mozilla
  • mydomai
  • noone
  • noreply
  • panda
  • rfc-ed
  • ripe.
  • root@
  • secure
  • sendmail
  • service
  • someone
  • spam
  • support
  • unix
  • update
  • usenet
  • winrar
  • winzip
  • www
  • xx
  • you
  • your

It then sends itself as an attachment to the gathered e-mail addresses using the following e-mail format: TO: {Gathered e-mail address from the system}FROM: The from field may use any of the following format:

  • %FirstName% %SecondName% <%FirstName%.%SecondName%@%domain name%>
  • %FirstName% <%SecondName%_%random%@%domain name%>
  • {Gathered e-mail address from the system}

Where %FirstName% may use any of the following:

  • adam
  • alice
  • anna
  • betty
  • bob
  • brenda
  • brent
  • brian
  • carol
  • claudia
  • craig
  • cyber
  • dan
  • dave
  • david
  • debby
  • den
  • Donna
  • frank
  • george
  • gerhard
  • helen
  • helen
  • james
  • jane
  • jayson
  • jerry
  • jim
  • joe
  • john
  • karen
  • linda
  • lisa
  • mancy
  • maria
  • ruth
  • sandra
  • sandra
  • sharon
  • Susan

%SecondName% may use any of the following:

  • adams
  • allen
  • anderson
  • baker
  • carter
  • clark
  • garcia
  • gonzalez
  • green
  • hall
  • harris
  • hernandez
  • hill
  • jackson
  • jeremy
  • joe
  • kenneth
  • king
  • lee
  • lewis
  • lopez
  • martin
  • martinez
  • miller
  • molly
  • moore
  • nelson
  • robinson
  • robyn
  • rodriguez
  • scott
  • shaan
  • taylor
  • thomas
  • thompson
  • walker
  • white
  • wilson
  • wright
  • young

%random% uses random 4-digit characters and %domain name% may use any of the following:

  • care2.com
  • email.myway.com
  • fastmail.fm
  • gmail.com
  • goowy.com
  • hotmail.com
  • inbox.com
  • mail.aim.com
  • mail.com
  • mail.lycos.com
  • yahoo.com

Examples:

  • james nelson (james.nelson@yahoo.com)
  • sandra (martin_1950@mail.aim.com)

SUBJECT: The subject may use any of the following strings:

  • Error
  • Good Day
  • Hello
  • Mail Delivery System
  • Mail server report
  • Mail Transaction Failed
  • Picture
  • Server Report
  • Status
  • Test

MESSAGE BODY: It may use any of the following messages:

  • Mail transaction failed. Partial message is available.
  • The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.
  • The message contains Unicode characters and has been sent as a binary attachment.
  • Mail server report. Our firewall determined the e-mails containing worm copies are being sent from your computer. Nowadays it happens from many computers, because this is a new virus type (Network Worms). Using the new bug in the Windows, these viruses infect the computer unnoticeably. After the penetrating into the computer the virus harvests all the e-mail addresses and sends the copies of itself to these e-mail addresses Please install updates for worm elimination and your computer restoring. Best regards, Customers support service

ATTACHMENT: The attachment is a copy of the worm. The filename is designed to disguise the executable nature of the attachment from the recipient. It is created using one of the following filename formats:

  • %filename%.%ext1%.%ext2%
  • Update-KB%random%-x86.exe

%filename% may use any of the following strings:

  • body
  • data
  • doc
  • docs
  • document
  • file
  • message
  • readme
  • test
  • text

%ext1% may use any of the following extension names:

  • dat
  • elm
  • log
  • msg
  • txt

%ext2% may use any of the following extension names:

  • bat
  • cmd
  • exe
  • pif
  • scr

%random% is composed of random numbers, for example:

  • readme.txt.scr
  • Update-KB1156-x86.exe

This worm also uses a text file icon in its attempt to fool recipients into thinking that this file is just a normal text or log file. This is especially true when the - Hide extensions for known file types - option in Windows is enabled. Below is an example. Readme.txt.scr will be displayed as:






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