Virus:Worm/Mytob.MC
Date discovered:03/12/2005
Type:Worm
In the wild:Yes
Reported Infections:Low
Distribution Potential:Medium to high
Damage Potential:Medium
Static file:Yes
File size:108.032 Bytes
MD5 checksum:6d7e8f6a1a27151de4c7e390eb554fd5
VDF version:6.32.01.03

 General Methods of propagation:
   • Email
   • Local network


Aliases:
   •  Symantec: W32.Mytob@mm
   •  Kaspersky: Backdoor.Win32.SdBot.xd
   •  TrendMicro: WORM_MYTOB.NF
   •  Sophos: W32/Dolebot-A
   •  Bitdefender: Backdoor.SDBot.AHZ


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


Side effects:
   • Drops a malicious file
   • Uses its own Email engine
   • Lowers security settings
   • Registry modification
   • Makes use of software vulnerability
   • Third party control

 Files It copies itself to the following location:
   • %WINDIR%\skype32.exe



It deletes the initially executed copy of itself.



The following file is created:

– %SYSDIR%\rofl.sys Detected as: BDS/Aimbot.AF.5

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

– HKLM\SYSTEM\CurrentControlSet\Services\Skype
   • "Type"=dword:00000110
   • "Start"=dword:00000002
   • "ErrorControl"=dword:00000000
   • "ImagePath"=%WINDIR%\skype32.exe
   • "DisplayName"="Skype Messenger"
   • "ObjectName"="LocalSystem"
   • "FailureActions"=%hex values%
   • "Description"="Skype Messenger Service"



The following registry key is added:

– HKLM\SYSTEM\CurrentControlSet\Control
   • "WaitToKillServiceTimeout"="7000"



The following registry keys are changed:

– HKLM\SOFTWARE\Microsoft\Security Center
   Old value:
   • "AntiVirusDisableNotify"=%user defined settings%
   • "FirewallDisableNotify"=%user defined settings%
   • "UpdatesDisableNotify"=%user defined settings%
   • "AntiVirusOverride"=%user defined settings%
   • "FirewallOverride"=%user defined settings%
   New value:
   • "AntiVirusDisableNotify"=dword:00000001
   • "FirewallDisableNotify"=dword:00000001
   • "UpdatesDisableNotify"=dword:00000001
   • "AntiVirusOverride"=dword:00000001
   • "FirewallOverride"=dword:00000001

Deactivate Windows Firewall:
– HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile
   Old value:
   • "EnableFirewall"=%user defined settings%
   New value:
   • "EnableFirewall"=dword:00000000

Deactivate Windows Firewall:
– HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile
   Old value:
   • "EnableFirewall"=%user defined settings%
   New value:
   • "EnableFirewall"=dword:00000000

– HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\
   Auto Update
   Old value:
   • "AUOptions"=%user defined settings%
   New value:
   • "AUOptions"=dword:00000001

– HKLM\SYSTEM\CurrentControlSet\Control\Lsa
   Old value:
   • "restrictanonymous"=%user defined settings%
   New value:
   • "restrictanonymous"=dword:00000001

– HKLM\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters
   Old value:
   • "AutoShareWks"=%user defined settings%
   • "AutoShareServer"=%user defined settings%
   New value:
   • "AutoShareWks"=dword:00000000
   • "AutoShareServer"=dword:00000000

– HKLM\SYSTEM\CurrentControlSet\Services\lanmanworkstation\parameters
   Old value:
   • "AutoShareWks"=%user defined settings%
   • "AutoShareServer"=%user defined settings%
   New value:
   • "AutoShareWks"=dword:00000000
   • "AutoShareServer"=dword:00000000

– HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
   Old value:
   • "DoNotAllowXPSP2"=%user defined settings%
   New value:
   • "DoNotAllowXPSP2"=dword:00000001

– HKLM\SOFTWARE\Microsoft\Ole
   Old value:
   • "EnableDCOM"=%user defined settings%
   New value:
   • "EnableDCOM"="N"

 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:
   • adb; asp; cfg; cgi; dbx; htm; html; jsp; mdb; msg; php; sht; tbb; txt;
      vbe; vbs; xml


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:
– MS03-026 (Buffer Overrun in RPC Interface)
– MS04-007 (ASN.1 Vulnerability)
– MS04-011 (LSASS Vulnerability)
– MS05-039 (Vulnerability in Plug and Play)

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

Server: tx.ha**********
Port: 43287
Channel: #dfnctsc
Nickname: [P00|USA|%five-digit random character string%]



– This malware has the ability to collect and send information such as:
    • Information about the network
    • Information about running processes


– Furthermore it has the ability to perform actions such as:
    • Download file
    • Execute file
    • Kill process
    • Perform network scan
    • Shut down system
    • Start spreading routine
    • Terminate malware
    • Terminate process
    • Updates itself

 Process termination  List of services that are disabled:
   • Security Center
   • Telnet
   • Remote Registry
   • Messenger

 Backdoor Contact server:
All of the following:
   • http://test.anonproxies.com/cgi-bin/**********
   • http://www21.big.or.jp/~mana_/**********
   • http://www.motor21.net/**********
   • http://www.xyerror.x-y.net/**********
   • http://www21.tok2.com/home/sophia/cgi-bin/**********


 Rootkit Technology It is a malware-specific technology. The malware hides its presence from system utilities, security applications and in the end, from the user.


Hides the following:
– Its own process

 File details Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with a runtime packer.

Description inserted by Irina Boldea on Friday, March 10, 2006
Description updated by Irina Boldea on Wednesday, March 15, 2006

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