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Virus:Worm/Mytob.61440
Date discovered:03/05/2005
Type:Worm
In the wild:Yes
Reported Infections:Low
Distribution Potential:Medium to high
Damage Potential:Medium
Static file:Yes
File size:58.368 Bytes
MD5 checksum:d4be7b51dee132f5814a3c7df7c5a464
IVDF version:6.30.00.154 - Tuesday, May 3, 2005

 General Methods of propagation:
   • Email
   • Local network


Aliases:
   •  Mcafee: W32/Mytob.gen@MM
   •  Kaspersky: Net-Worm.Win32.Mytob.gen
   •  TrendMicro: WORM_MYDOOM.DM
   •  F-Secure: Net-Worm.Win32.Mytob.gen
   •  Sophos: W32/Mytob-BT
   •  Panda: W32/Mytob.CD.worm
   •  Eset: Win32/Mytob.BL worm
   •  Bitdefender: Win32.Worm.Mytob.LM


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


Side effects:
   • Blocks access to security websites
   • Uses its own Email engine
   • Third party control

 Files It copies itself to the following locations:
   • %SYSDIR%\taskgmrs.exe
   • c:\funny_pic.scr
   • c:\see_this!!.scr
   • c:\my_photo2005.scr



The following file is created:

c:\hellmsn.exe Furthermore it gets executed after it was fully created. Further investigation pointed out that this file is malware, too. Detected as: Worm/Mytob.F.1

 Registry The following registry keys are added in order to run the processes after reboot:

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • "WINDRUN"="taskgmrs.exe"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   • "WINDRUN"="taskgmrs.exe"



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

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices]
   • "WINDRUN"="taskgmrs.exe"



The following registry keys are added:

[HKCU\Software\Microsoft\OLE]
   • "WINDRUN"="taskgmrs.exe"

[HKCU\SYSTEM\CurrentControlSet\Control\Lsa]
   • "WINDRUN"="taskgmrs.exe"

[HKLM\SOFTWARE\Microsoft\Ole]
   • "EnableDCOM"="Y"
   • "WINDRUN"="taskgmrs.exe"

[HKLM\SYSTEM\CurrentControlSet\Control\Lsa]
   • "WINDRUN"="taskgmrs.exe"

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


From:
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.
The sender of the email is one of the following:
   • sandra
   • lolita
   • britney
   • bush
   • linda
   • julie
   • jimmy
   • jerry
   • helen
   • debby
   • claudia
   • brenda
   • anna
   • madmax
   • brent
   • adam
   • ted
   • fred
   • jack
   • bill
   • stan
   • smith
   • steve
   • matt
   • dave
   • dan
   • joe
   • jane
   • bob
   • robert
   • peter
   • tom
   • ray
   • mary
   • serg
   • brian
   • jim
   • maria
   • leo
   • jose
   • andrew
   • sam
   • george
   • david
   • kevin
   • mike
   • james
   • michael
   • alex
   • john


To:
– Email addresses found in specific files on the system.


Subject:
One of the following:
   • hello
   • Error
   • Status
   • Good day
   • SERVER REPORT
   • Mail Transaction Failed
   • Mail Delivery System

In some cases the subject might also be empty.
Furthermore the subject line could contain random letters.


Body:
–  In some cases it may contain random characters.
The body of the email is one of the lines:
   • Mail transaction failed. Partial message is available.
   • The message contains Unicode characters and has been sent as a binary attachment.
   • The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.
   • The original message was included as an attachment.
   • Here are your banks documents.


Attachment:
The filename of the attachment is constructed out of the following:

–  It starts with one of the following:
   • doc
   • file
   • text
   • data
   • body
   • readme
   • message
   • document
   • %random character string%

    The file extension is one of the following:
   • .zip
   • .scr
   • .pif
   • .bat
   • .exe
   • .cmd



The email looks like the following:


 Mailing Search addresses:
It searches the following files for email addresses:
   • wab
   • adbh
   • tbbg
   • dbxn
   • aspd
   • phpq
   • shtl
   • htmb


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

 Network Infection Exploit:
It makes use of the following Exploit:
– 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: irc.beast**********
Port: 8080
Channel: #hell
Nickname: [I]%random character string%
Password: hellabot


 Furthermore it has the ability to perform actions such as:
     disconnect from IRC server
    • Enable network shares
    • Execute file
    • Join IRC channel
    • Kill process
    • 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;
      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; www.microsoft.com; www.trendmicro.com




The modified host file will look like this:


 Backdoor The following port is opened:

taskgmrs.exe on TCP port 10082 in order to provide an FTP server.

 Miscellaneous Mutex:
It creates the following Mutex:
   • H-E-L-L-B-O-T

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

Description inserted by Gabriel Mustata on Friday, October 5, 2007
Description updated by Gabriel Mustata on Friday, October 5, 2007

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