1. Symantec/
  2. Security Response/
  3. W32.Sober.I@mm


Risk Level 2: Low

November 19, 2004
February 13, 2007 12:30:07 PM
Also Known As:
Win32.Sober.I [Computer Associ, Sober.I [F-Secure], I-Worm.Sober.i [Kaspersky], W32/Sober.j@MM [McAfee], W32/Sober.I@mm [Norman], W32/Sober.I.worm [Panda], W32/Sober-I [Sophos], WORM_SOBER.I [Trend]
Systems Affected:

When W32.Sober.I@mm is executed, it performs the following actions:
  1. Displays the following message:

    "WinZip_Data_Module is missing ~Error: {[random number]}"

  2. Creates two files in the %System% folder using a file name composed of the following strings:

    • sys
    • host
    • dir
    • expoler
    • win
    • run
    • log
    • 32
    • disc
    • crypt
    • data
    • diag
    • spool
    • service
    • smss32

      Note: %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).

  3. Creates the following files:

    • %System%\nonzipsr.noz
    • %System%\clonzips.ssc
    • %System%\clsobern.isc
    • %System%\sb2run.dii
    • %System%\winsend32.dal
    • %System%\winroot64.dal
    • %System%\zippedsr.piz
    • %System%\winexerun.dal
    • %System%\winmprot.dal
    • %System%\dgssxy.yoi
    • %System%\cvqaikxt.apk
    • %System%\sysmms32.lla
    • %System%\Odin-Anon.Ger

  4. Adds the values:

    "[random value name]" = "%System%\[random worm file name].exe"
    "[random value name]" = "%System%\[random worm file name].exe %srun%"

    to the registry key:


    so that the worm is executed every time Windows starts.

    Note: [random value name] is composed of one or more of the following strings:

    • sys
    • host
    • dir
    • expoler
    • win
    • run
    • log
    • 32
    • disc
    • crypt
    • data
    • diag
    • spool
    • service
    • smss32

  5. If the current date has passed January 5, 2005, then the worm may attempt to download and execute a file from multiple locations on the following domains:

    • home.arcor.de
    • scifi.pages.at
    • home.pages.at
    • free.pages.at
    • people.freenet.de

      This file is detected as Trojan.Dimi.

  6. Gathers email addresses from files on the infected computer.

    It avoids the email addresses that contain the following strings:

    • office
    • @www
    • @from.
    • support
    • redaktion
    • smtp-
    • @smtp.
    • gold-certs
    • ftp.
    • .dial.
    • .ppp.
    • anyone
    • subscribe
    • announce
    • @gmetref
    • sql.
    • someone
    • nothing
    • you@
    • user@
    • reciver@
    • somebody
    • secure
    • msdn.
    • me@
    • whatever@
    • whoever@
    • anywhere
    • yourname
    • mustermann@
    • .kundenserver.
    • mailer-daemon
    • variabel
    • password
    • -dav
    • law2
    • .sul.t-
    • .qmail@
    • t-ipconnect
    • t-dialin
    • ipt.aol
    • time
    • postmas
    • service
    • freeav
    • @ca.
    • abuse
    • winrar
    • domain.
    • host.
    • viren
    • bitdefender
    • spybot
    • detection
    • ewido.
    • emsisoft
    • linux
    • google
    • @foo.
    • winzip
    • @example.
    • bellcore.
    • @arin
    • mozilla
    • @iana
    • @avp
    • @msn
    • icrosoft.
    • @spiegel.
    • @sophos
    • @panda
    • @kaspers
    • free-av
    • antivir
    • virus
    • verizon.
    • @ikarus.
    • @nai.
    • @messagelab
    • nlpmail01.
    • clock
    • track.
    • www.
    • members.
    • clicks.
    • refer.

  7. Checks the network connection by contacting an NTP server on TCP port 37, or by resolving one of the following domains:

    • microsoft.com
    • bigfoot.com
    • yahoo.com
    • t-online.de
    • google.com
    • hotmail.com
    • ns1.interplanet.com.mx

  8. Sends a copy of itself as an email attachment to the addresses that it finds on the infected computer, using its own SMTP Engine. The email messages will be in either English or German and will have the following characteristics:

    The From line can be an email address found on the infected computer or comprised of the following:

    [fake sender name]@[recipient's domain]

    where [fake sender name] is one of the following:

    • Info
    • FehlerMail
    • Webmaster
    • ReMailer
    • Lisa
    • Peter
    • Michael
    • Thomas
    • Elke
    • Susi
    • Nadine
    • Benutzer-Daten
    • Information
    • Service
    • Hilfe
    • Webmaster
    • Hostmaster
    • Postmaster
    • User-Info

      and [recipient's domain] is the domain of the intended receiver of the email.

      Subject: One of the following:

    • FwD: hi there
    • FwD: hey dude!
    • FwD: wazzup!!!
    • FwD: yeah dude :P
    • FwD: Details
    • FwD: Oh God it's
    • FwD: damn!
    • FwD: #
    • FwD: Registration confirmation
    • FwD: Confirmation
    • FwD: Your Password
    • FwD: Your mail account
    • FwD: Delivery failure notice
    • FwD: Faulty mail delivery
    • FwD: Mail delivery failed
    • FwD: Mailing Error
    • FwD: Illegal signs in E-Mail
    • FwD: Invalid mail length
    • FwD: Mail Delivery failure
    • FwD: mail delivery status
    • FwD: Warning!
    • FwD: error in dbase
    • FwD: DBase Error
    • FwD: ups, i've got your mail
    • FwD: Sorry, that's your mail
    • FwD: why do you do that?
    • FwD: Life's a Bitch
    • FwD: Smiling Like a Killer
    • FwD: lol,wat'nlosey?
    • FwD: Informationvon
    • FwD: FalscheMailzustellung
    • FwD: FehlerinIhrerE-Mail
    • FwD: IhreE-Mailwarfehlerhaft
    • FwD: ESMTPError
    • FwD: UngültigeVariableninihrerE-Mail
    • FwD: Verbindungwurdegetrennt
    • FwD: Mail_Fehler
    • FwD: IhrneuerAccount
    • FwD: NeueAccountDaten
    • FwD: Siehabennichtgezahlt
    • FwD: Rechnung
    • FwD: Hi,seivorsichtig!
    • FwD: Achtung!gefährlicherVirus!
    • FwD: Schongehört?
    • FwD: DieTools!
    • FwD: DeinZeug's!
    • FwD: Hierfürdich^^
    • FwD: BestellungsBestätigung
    • FwD: Lieferungs-Bestätigung
    • FwD: Ok,hieristmein
    • FwD: Ichhabemichindichv

      Body: May be composed of some of the following text:

      ++++ User-Service: http:/ /www.<sender's domain>
      ++++ MailTo: postmaster@<sender's domain>

      Your password was changed successfully.

      Protected message is attached.

      This account_hast_been_disabled.


      Diese Information ist geschützt duch ein Passwort!

      Da Sie uns Ihre Persönlichen Daten zugesandt haben, ist das Passwort Ihr Geburts-Datum.

      Viel vergnügen mit unserem Angebot!

      Im I-Net unter: http:www.[domain]

      Aus Datenschutzrechtlichen Gründen, darf die vollständige E'Mail incl. Daten nur angehängt werden.

      Wir bitten Sie, dieses zu berücksichtigen.

      GmBH & Co. KG

      Da unsere Datenbanken leider durch einen Programm Fehler zerstört wurden, mussten wir leider eine änderung bezüglich Ihrer Nutzungs- Daten vornehmen.
      Ihre geänderten Account Daten, befinden sich im beigefügten Dokument.


      This mail was generated automatically.
      More info about --GAYNET-- under: http:/ /www.gaynet.ch


      # 440: MAILBOX NOT FOUND


      The full mail is attached.

      Auto_Mail.System: [gaynet]

      *-*-* Mail_Scanner: No Virus
      *-*-* SYMANTEC- Anti_Virus Service


      I was surprised, too!
      Who_could_suspect_something_like_that? sh*tyiiiii


      --------------This mail was generated automatically.
      More info about --HOTMAIL-- under: http:/ /www.hotmail.com


      # 153: Giving_up_on_[IP]


      The full mail is attached.

      Auto_Mail.System: [hotmail]

      *-*-* Mail_Scanner: No Virus
      *-*-* SYMANTEC- Anti_Virus Service

      The attachment may be based on an email address found on the infected computer or may be one of the following, with a .pif, .zip, .scr, .bat or .com extension:

    • im_shocked
    • oh_nono
    • thats_hard
    • mail
    • auto_mail
    • re-mail_system
    • Error_mail

      The attachment may also be named [recipient's domain].[first extension].zip where [first extension] is one of the following:

    • .txt
    • .doc
    • .word
    • .xls
    • .eml
    • .TXT
    • .DOC
    • .EML


Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
Writeup By: Candid Wueest
Summary| Technical Details| Removal

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