WORM_MYDOOM.NZU

This Worm arrives as an attachment to email messages mass-mailed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It gathers target email addresses from the Windows Address Book (WAB).

As of this writing, the said sites are inaccessible.

Arrival Details

This Worm arrives as an attachment to email messages mass-mailed by other malware/grayware or malicious users.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Worm drops the following copies of itself into the affected system:

• %Windows%\java.exe
• %User Temp%\java.exe

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It drops the following component file(s):

• %Windows%\services.exe - detected as WORM_MYDOOM.NM
• %User Temp%\services.exe - detected as WORM_MYDOOM.NM

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Autostart Technique

This Worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
JavaVM = "%Windows%\java.exe" or "%User Temp%\java.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Services = "%Windows%\services.exe" or "%User Temp%\services.exe"

Other System Modifications

This Worm adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Daemon

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Daemon

Propagation

This Worm gathers target email addresses from files with the following extensions:

• .pl
• .asp
• .sht
• .adb
• .dbx
• .wab

It gathers target email addresses from the Windows Address Book (WAB).

It avoids sending email messages to addresses containing the following strings:

• mailer-d
• spam
• abuse
• master
• sample
• accoun
• privacycertific
• bugs
• listserv
• submit
• ntivi
• support
• admin
• page
• the.bat
• gold-certs
• feste
• not
• help
• foo
• soft
• site
• rating
• you
• your
• someone
• anyone
• nothing
• nobody
• noone
• info
• winrar
• winzip
• rarsoft
• sf.net
• sourceforge
• ripe.
• arin.
• google
• gnu.
• gmail
• seclist
• secur
• bar.
• foo.com
• trend
• update
• uslis
• domain
• example
• sophos
• yahoo
• spersk
• panda
• hotmail
• msn.
• msdn.
• microsoft
• sarc.
• syma
• avp

Dropping Routine

This Worm drops the following files:

• %User Temp%\tmp{random}.tmp - either a zip file used as an attachment, or copy of itself
• %User Temp%\zincite.log
• %User Temp%\{random characters}.log

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Download Routine

This Worm connects to the following website(s) to download and execute a malicious file:

• http://www.{BLOCKED}heap.co.uk/iblog/Applepiona.jpg
• http://www.{BLOCKED}erationcomics.net/banner/NGCbanren.jpg
• http://www.{BLOCKED}ridge.org.uk/YaBBImages/adnim.gif
• http://www.{BLOCKED}astchoons.co.uk/4play/DSCN2747.JPG
• http://www.{BLOCKED}ha.com/charte/contraste.jpg
• http://www.{BLOCKED}riders.co.uk/images/pixel_blue.gif
• http://www.{BLOCKED}ha.com/charte/contraste.jpg
• http://www.{BLOCKED}g.org/archives/DSCN0622.JPG
• http://www.{BLOCKED}rada.net/banners/genteite.gif
• http://{BLOCKED}s.net/banner/NGCbanren.jpg

It saves the files it downloads using the following names:

• {malware path}\ona.jpg

As of this writing, the said sites are inaccessible.

Other Details

This Worm does the following:

• The email message it sends out may have the following characteristics:
• From:
  • postmaster@{target domain}
  • MAILER-DAEMON@{target domain}
  • noreply@{target domain}
• It uses the following display names:
  • Postmaster
  • Mail Administrator
  • Automatic Email Delivery Software
  • Post Office
  • The Post Office
  • Bounced mail
  • Returned mail
  • MAILER-DAEMON
  • Mail Delivery Subsystem
• Subject:
  • hello
  • error
  • status
  • test
  • report
  • delivery failed
  • Message could not be delivered
  • Mail System Error - Returned Mail
  • Delivery reports about your e-mail
  • Returned mail: see transcript for details
  • Returned mail: Data format error
• Body:

  Dear user {$t|of $T},{ {{M|m}ail {system|server} administrator|administration} of $T would like to {inform you{ that{:|,}|}|let you know {that|the following}{.|:|,}}|||||}
  {We have {detected|found|received reports} that y|Y}our {e{-|}mail |}account {has been|was} used to send a {large|huge} amount of {{unsolicited{ commercial|}|junk} e{-|}mail|spam}{ messages|} during {this|the {last|recent}} week.
  {We suspect that|Probably,|Most likely|Obviously,} your computer {had been|was} {compromised|infected{ by a recent v{iru}s|}} and now {run|contain}s a {trojan{ed|}|hidden} proxy server.
  {Please|We recommend {that you|you to}} follow {our |the |}instruction{s|} {in the {attachment|attached {text |}file} |}in order to keep your computer safe.
  {{Virtually|Sincerely} yours|Best {wishe|regard}s|Have a nice day},
  {$T {user |technical |}support team.|The $T {support |}team.}
  
  {The|This|Your} message was{ undeliverable| not delivered} due to the following reason{(s)|}:
  Your message {was not|could not be} delivered because the destination {computer|server} was
  {not |un}reachable within the allowed queue period. The amount of time
  a message is queued before it is returned depends on local configura-
  tion parameters.
  Most likely there is a network problem that prevented delivery, but
  it is also possible that the computer is turned off, or does not
  have a mail system running right now.
  
  Your message {was not|could not be} delivered within $D days:
  {{{Mail s|S}erver}|Host} $i is not responding.
  The following recipients {did|could} not receive this message:
  <$t>
  Please reply to postmaster@{$F|$T}
  if you feel this message to be in error.
  The original message was received at $w{
  | }from {$F [$i]|{$i|[$i]}}
  ----- The following addresses had permanent fatal errors -----
  {<$t>|$t}
  {----- Transcript of {the ||}session follows -----
  ... while talking to {host |{mail |}server ||||}{$T.|$i}:
  {>>> MAIL F{rom|ROM}:$f
  <<< 50$d {$f... |}{Refused|{Access d|D}enied|{User|Domain|Address} {unknown|blacklisted}}|554 <$t>... {Mail quota exceeded|Message is too large}
  554 <$t>... Service unavailable|550 5.1.2 <$t>... Host unknown (Name server: host not found)|554 {5.0.0 |}Service unavailable; [$i] blocked using {relays.osirusoft.com|bl.spamcop.net}{, reason: Blocked|}
  Session aborted{, reason: lost connection|}|>>> RCPT To:<$t>
  <<< 550 {MAILBOX NOT FOUND|5.1.1 <$t>... {User unknown|Invalid recipient|Not known here}}|>>> DATA
  {<<< 400-aturner; %MAIL-E-OPENOUT, error opening !AS as output
  |}{<<< 400-aturner; -RMS-E-CRE, ACP file create failed
  |}{<<< 400-aturner; -SYSTEM-F-EXDISKQUOTA, disk quota exceeded
  |}<<< 400}|}
  The original message was included as attachment
  
  {{The|Your} m|M}essage could not be delivered

• It attaches a copy of itself in a .ZIP file. It may use the target email address name as the filename of the attachment, or any of the following:
  • readme
  • instruction
  • transcript
  • mail
  • letter
  • file
  • text
  • attachment
  • document
  • message
• The copy of itself in the attachment may have the following extension:
  • .cmd
  • .bat
  • .com
  • .exe
  • .pif
  • .scr
• The copy of itself in the attachment may have the following fake extension:
  • .doc
  • .txt
  • .htm
  • .html
• This worm queries from the following search engines to harvest email addresses from the results of the queries:
  • http://search.lycos.com
  • http://search.yahoo.com
  • http://www.altavista.com
  • http://www.google.com
• It will also harvest email addresses from any active Outlook window on the affected machine.