SymbOS.Doomboot.M

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Discovered: November 10, 2005
Updated: February 13, 2007 12:46:19 PM
Also Known As: SYMBOS_DOOMED.H [Trend Micro]
Type: Trojan Horse
Systems Affected: EPOC


SymbOS.Doomboot.M is a Trojan horse that drops corrupt files on to the compromised device. The Trojan runs on the Symbian operating system that is used in Nokia Series 60 cellular telephones.

The Trojan arrives as exoVirusStop v2.13.16.sis (63,393 bytes), disguising itself as an antivirus product.

Antivirus Protection Dates

  • Initial Rapid Release version November 10, 2005
  • Latest Rapid Release version August 20, 2008 revision 017
  • Initial Daily Certified version November 10, 2005
  • Latest Daily Certified version August 20, 2008 revision 016
  • Initial Weekly Certified release date November 16, 2005

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Yana Liu

Discovered: November 10, 2005
Updated: February 13, 2007 12:46:19 PM
Also Known As: SYMBOS_DOOMED.H [Trend Micro]
Type: Trojan Horse
Systems Affected: EPOC


When SymbOS.Doomboot.M is executed, it performs the following actions:

    1. Displays a message that warns users that the application may be coming from an untrusted source and may cause potential problems when installed on the mobile device

    2. Displays a message prompting the user to Install:

      "exoVirusStop v 2.13.16"

    3. May displays the following warning message to the user:

      "Application may not be compatbile with phone. Quit Installation?"

    4. After Installation displays the following message to the User:

      "For Updates visit www.exosyphenstudio.com. If there is a virus re-boot your phone after disinfection"

    5. Drops the following corrupt files onto the C drive of the compromised device:

      • C:\Etel.dll
      • C:\etelmm.dll
      • C:\etelpckt.dll
      • C:\etelsat.dll

        Note: When the device is restarted, these files will be loaded and the device will not function correctly.

    6. Drops the following files:

      • C:\system\apps\Cabir AA detected\Cabir AA detected EVS is disinfecting re-boot your phone.rsc - 0 bytes
      • C:\system\apps\Cabir AA detected\Cabir AA detected EVS is disinfecting re-boot your phone.MBM - 0 bytes
      • C:\system\apps\Cabir AA detected\Cabir AA detected EVS is disinfecting re-boot your phone.app - 0 bytes
      • C:\system\apps\Cabir AA detected\Cabir AA detected EVS is disinfecting re-boot your phone.app - 0 bytes
      • C:\system\apps\velasco\marcos.mdl - 0 bytes
      • C:\system\apps\velasco\velasco.app - 0 bytes
      • C:\system\apps\velasco\velasco.rsc - 0 bytes
      • C:\system\install\exoVirusStop v2.13.16.sis
      • C:\Nokia\installs\exoVirusStop v2.13.16.sis

    7. Drops the following files, which are associated with a legitimate AntiVirus product:

      • C:\system\apps\EVS\EVS.aif - 3,245 bytes
      • C:\system\apps\EVS\EVS.app - 30,368 bytes
      • C:\system\apps\EVS\EVS.rsc - 671 bytes
      • C:\system\apps\EVS\EVS_caption.rsc - 60 bytes
      • C:\system\apps\EVS\exovirusstop.mbm - 3,961 bytes


      Recommendations

      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: Yana Liu

      Discovered: November 10, 2005
      Updated: February 13, 2007 12:46:19 PM
      Also Known As: SYMBOS_DOOMED.H [Trend Micro]
      Type: Trojan Horse
      Systems Affected: EPOC



      1. Install a file manager program on the device.

      2. Enable the option to view the files in the system folder.

      3. Delete the following malicious files:

        • C:\Etel.dll
        • C:\etelmm.dll
        • C:\etelpckt.dll
        • C:\etelsat.dll
        • C:\system\install\exoVirusStop v2.13.16.sis
        • C:\Nokia\installs\exoVirusStop v2.13.16.sis

      4. Delete the following non-malicious files:

        • C:\system\apps\Cabir AA detected\Cabir AA detected EVS is disinfecting re-boot your phone.rsc (0 bytes)
        • C:\system\apps\Cabir AA detected\Cabir AA detected EVS is disinfecting re-boot your phone.MBM (0 bytes)
        • C:\system\apps\Cabir AA detected\Cabir AA detected EVS is disinfecting re-boot your phone.app (0 bytes)
        • C:\system\apps\Cabir AA detected\Cabir AA detected EVS is disinfecting re-boot your phone.app (0 bytes)
        • C:\system\apps\velasco\marcos.mdl (0 bytes)
        • C:\system\apps\velasco\velasco.app (0 bytes)
        • C:\system\apps\velasco\velasco.rsc (0 bytes)

      5. If you are not currently using exoVirusStop you can remove it by deleting the following files:

        • C:\system\apps\EVS\EVS.aif (3,245 bytes)
        • C:\system\apps\EVS\EVS.app (30,368 bytes)
        • C:\system\apps\EVS\EVS.rsc (671 bytes)
        • C:\system\apps\EVS\EVS_caption.rsc (60 bytes)
        • C:\system\apps\EVS\exovirusstop.mbm (3,961 bytes)

      6. Exit the file manager.


      Writeup By: Yana Liu