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Virus:Worm/Mytob.LZ
Date discovered:28/11/2005
Type:Worm
In the wild:Yes
Reported Infections:Low
Distribution Potential:Medium to high
Damage Potential:Medium
Static file:Yes
File size:94.689 Bytes
MD5 checksum:2f172aa5095904316ae33e5d04edffb5
VDF version:6.32.00.233

 General Methods of propagation:
   • Email
   • Local network


Aliases:
   •  Symantec: W32.Mytob@mm
   •  Kaspersky: Net-Worm.Win32.Mytob.cu
   •  TrendMicro: WORM_MYTOB.NB
   •  F-Secure: Net-Worm.Win32.Mytob.cu
   •  Sophos: W32/Mytob-FZ
   •  Panda: W32/Mydoom.CA.worm
   •  VirusBuster: I-Worm.Mytob.OP
   •  Eset: Win32/Mytob.NE
   •  Bitdefender: Win32.Worm.MyTob.DL


Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003


Side effects:
   • Uses its own Email engine
   • Registry modification
   • Makes use of software vulnerability
   • Steals information
   • Third party control

 Files It copies itself to the following location:
   • %SYSDIR%\msconfgh.exe

 Registry The following registry keys are continuously in an infinite loop added in order to run the processes after reboot.

  HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   • "Win32 Cnfg32" = "msconfgh.exe"

  HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
   • "Win32 Cnfg32" = "msconfgh.exe"

  HKCU\Software\Microsoft\Windows\CurrentVersion\Run
   • "Win32 Cnfg32" = "msconfgh.exe"

  HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce
   • "Win32 Cnfg32" = "msconfgh.exe"



The following registry keys are added in order to load the service after reboot:

HKLM\SYSTEM\CurrentControlSet\Services\Win32 Cnfg32
   • "Type"=dword:00000020
   • "Start"=dword:00000004
   • "ErrorControl"=dword:00000001
   • "ImagePath"="%SYSDIR%\msconfgh.exe"
   • "DisplayName"="Win32 Cnfg32"
   • "ObjectName"="LocalSystem"
   • "FailureActions"=%hex values%
   • "DeleteFlag"=dword:00000001

 Email It contains an integrated SMTP engine in order to send emails. A direct connection with the destination server will be established. The characteristics are described in the following:


From:
The sender address is spoofed.
Generated addresses. Please do not assume that it was the sender's intention to send this email to you. He might not know about his infection or might not even be infected at all. Furthermore it is possible that you will receive bounced emails telling you that you are infected. This might also not be the case.


To:
– Email addresses found in specific files on the system.
 Email addresses gathered from WAB (Windows Address Book)
– Generated addresses


Subject:
One of the following:
   • Notice of account limitation
   • Email Account Suspension
   • Security measures
   • Members Support
   • Important Notification
   • Warning Message: Your services near to be closed.
   • Your Account is Suspended For Security Reasons
   • *DETECTED* Online User Violation
   • Your Account is Suspended
   • Your new account password is approved
   • You have successfully updated your password
   • Your password has been successfully updated
   • Your password has been updated

Furthermore the subject line could contain random letters.


Body:
The body of the email is one of the following:

   • Dear %receiver's domain name from email address% Member,
     We have temporarily suspended your email account %receiver's email address%
     This might be due to either of the following reasons:
     1. A recent change in your personal information (i.e. change of address).
     2. Submiting invalid information during the initial sign up process.
     3. An innability to accurately verify your selected option of subscription due to an internal error within our processors.
     See the details to reactivate your %receiver's domain name from email address% account.
     Sincerely,The %sender's domain name from email address% Support Team
     
     +++ Attachment: No Virus (Clean)
     +++ %sender's domain name from email address% Antivirus - www.%sender's domain name from email address%

   • Dear user %username from receiver's email address% ,
     You have successfully updated the password of your %receiver's domain name from email address% account.
     If you did not authorize this change or if you need assistance with your account, please contact %sender's domain name from email address% customer service at: %sender's email address%
     Thank you for using%sender's domain name from email address%!
     The %sender's domain name from email address% Support Team
     
     +++ Attachment: No Virus (Clean)
     +++ %sender's domain name from email address% Antivirus - www.%sender's domain name from email address%

   • Dear%receiver's domain name from email address% Member,
     Your e-mail account was used to send a huge amount of unsolicited spam messages during the recent week. If you could please take 5-10 minutes out of your online experience and confirm the attached document so you will not run into any future problems with the online service.
     
     If you choose to ignore our request, you leave us no choice but to cancel your membership.
     Virtually yours,
     The %sender's domain name from email address% Support Team
     
     +++ Attachment: No Virus found
     +++%sender's domain name from email address% Antivirus - www.%sender's domain name from email address%

   • Dear user %username from receiver's email address% ,
     It has come to our attention that your %sender's domain name from email address% User Profile ( x ) records are out of date. For further details see the attached document.
     Thank you for using %sender's domain name from email address% !
     The %sender's domain name from email address% Support Team
     
     +++ Attachment: No Virus (Clean)
     +++ %sender's domain name from email address% Antivirus - www.%sender's domain name from email address%


Attachment:
The filename of the attachment is one of the following:
   • accepted-password.zip
   • account-details.zip
   • account-info.zip
   • account-password.zip
   • account-report.zip
   • approved-password.zip
   • document.zip
   • email-details.zip
   • email-password.zip
   • important-details.zip
   • new-password.zip
   • password.zip
   • readme.zip
   • updated-password.zip
   • %random character string%.zip

The attachment is an archive containing a copy of the malware itself.



The email looks like the following:


 Mailing Search addresses:
It searches the following files for email addresses:
   • wab; adb; tbb; dbx; asp; php; sht; htm; html; xml; cgi; jsp; txt; tmp


Address generation for FROM field:
To generate addresses it uses the following strings:
   • webmaster
   • register
   • info
   • admin
   • service
   • mail
   • administrator
   • support



Address generation for TO field:
To generate addresses it uses the following strings:
   • adam; alex; andrew; anna; bill; bob; brenda; brent; brian; claudia;
      dan; dave; david; debby; frank; fred; george; helen; jack; james;
      jane; jerry; jim; jimmy; joe; john; jose; josh; julie; kevin; leo;
      linda; maria; mary; matt; michael; mike; paul; peter; ray; robert;
      sales; sam; sandra; serg; smith; stan; steve; ted; tom



Avoid addresses:
It does not send emails to addresses containing one of the following strings:
   • .edu; .gov; .mil; abuse; accoun; acketst; admin; ahn; antivi; anyone;
      arin.; avp; be_loyal:; berkeley; borlan; bsd; bugs; certific; contact;
      duba; example; fbi; fcnz; feste; fido; foo.; f-pro; freeav; f-secur;
      fsf.; gnu; gold-certs; google; gov.; help; hotmail; iana; ibm.com;
      icrosof; icrosoft; ietf; info; inpris; isc.o; isi.e; jiangmin;
      kaspersky; kernel; linux; listserv; master; math; mcafee; messagelabs;
      mit.e; mozilla; msn.; mydomai; nobody; nodomai; noone; norman; norton;
      not; nothing; ntivi; page; panda; pgp; postmaster; privacy; rating;
      rfc-ed; ripe.; rising; root; ruslis; samples; sdbot; secur; sendmail;
      service; site; slashdot; soft; somebody; someone; sopho; sourceforge;
      spm; submit; support; syma; symantec; tanford.e; the.bat; unix;
      usenet; utgers.ed; viruslis; webmaster; www; you; your


Prepend MX strings:
In order to get the IP address of the mail server it has the ability to prepend the following strings to the domain name:
   • mx.
   • mail.
   • smtp.
   • mx1.
   • mxs.
   • mail1.
   • relay.
   • ns.
   • gate.

 Network Infection In order to ensure its propagation the malware attemps to connect to other machines as described below.


Exploit:
It makes use of the following Exploits:
– MS04-007 (ASN.1 Vulnerability)
– MS04-011 (LSASS Vulnerability)


IP address generation:
It creates random IP addresses while it keeps the first two octets from its own address. Afterwards it tries to establish a connection with the created addresses.


Infection process:
Creates an FTP script on the compromised machine in order to download the malware to the remote location.

 IRC To deliver system information and to provide remote control it connects to the following IRC Server:

Server: f00r.dy**********
Port: 6667
Channel: #tob
Password: (null)



 This malware has the ability to collect and send information such as:
    • Cached passwords
    • CPU speed
     Details about drivers
    • Free disk space
    • Free memory
    • Malware uptime
    • Information about the network
    • Information about running processes
    • Size of memory
    • Username
    • Information about the Windows operating system


 Furthermore it has the ability to perform actions such as:
     Launch DDoS SYN flood
     Launch DDoS UDP flood
    • Download file
    • Execute file
    • Kill process
     Perform network scan
    • Perform port redirection
    • Restart system
    • Send emails
    • Shut down system
     Start keylog
     Start spreading routine
    • Terminate malware
    • Terminate process
     Updates itself
    • Upload file

 Hosts The host file is modified as explained:

In this case already existing entries remain unmodified.

Access to the following domains is effectively blocked:
   • www.symantec.com; securityresponse.symantec.com; symantec.com;
      www.sophos.com; sophos.com; www.mcafee.com; mcafee.com;
      liveupdate.symantecliveupdate.com; www.viruslist.com; viruslist.com;
      viruslist.com; f-secure.com; www.f-secure.com; kaspersky.com;
      kaspersky-labs.com; www.avp.com; www.kaspersky.com; avp.com;
      www.networkassociates.com; networkassociates.com; www.ca.com; ca.com;
      mast.mcafee.com; my-etrust.com; www.my-etrust.com;
      download.mcafee.com; dispatch.mcafee.com; secure.nai.com; nai.com;
      www.nai.com; update.symantec.com; updates.symantec.com; us.mcafee.com;
      liveupdate.symantec.com; customer.symantec.com; rads.mcafee.com;
      trendmicro.com; pandasoftware.com; www.pandasoftware.com;
      www.trendmicro.com; www.grisoft.com; www.microsoft.com; microsoft.com;
      www.virustotal.com; virustotal.com; www.amazon.com; www.amazon.co.uk;
      www.amazon.ca; www.amazon.fr; www.paypal.com; paypal.com;
      moneybookers.com; www.moneybookers.com; www.ebay.com; ebay.com




The modified host file will look like this:


 Backdoor The following port is opened:

%SYSDIR%\msconfgh.exe on a random TCP port in order to provide an FTP server.

 Stealing  It uses a network sniffer that checks for the following strings:
   • :.login
   • :!login
   • :.secure
   • :!advscan
   • :.advscan
   • :.ipscan
   • :!ident
   • :.ident

A logging routine is started after the following website is visited, which contains one of the following substrings in the URL:
   • paypal
   • PAYPAL
   • paypal.com
   • PAYPAL.COM

 It captures:
     Internet traffic
     Login information

 File details Programming language:
The malware program was written in MS Visual C++.


Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with the following runtime packer:
   • MEW

Description inserted by Irina Boldea on Friday, March 31, 2006
Description updated by Irina Boldea on Wednesday, April 19, 2006

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