SymbOS.Cabir.O

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Discovered: January 05, 2005
Updated: February 13, 2007 12:31:40 PM
Type: Worm
Systems Affected: EPOC



SymbOS.Cabir.O is a proof-of-concept worm that replicates on Series 60 phones. The worm is a minor variant of SymbOS.Cabir .

The only differences are:

  • The worm spreads as mobile.SIS.
  • The worm displays the following message after infection:

    mobile

The worm repeatedly sends itself to the first Bluetooth-enabled device that it can find, regardless of the type of device. For example, even a Bluetooth-enabled printer will be attacked if it is within range.

The worm spreads as a .SIS file, which is installed into the APPS directory. There is no payload, apart from the vastly shortened battery life caused by the constant scanning for Bluetooth-enabled devices.



Symantec recommends the following to protect against this threat:
  • If Bluetooth is not required, it should be turned off.
  • If you require the use of Bluetooth, ensure that the device's visibility setting is set to "Hidden" so that it can not be scanned by other Bluetooth devices.
  • Avoid use of device pairing. If it must be used, ensure that all paired devices are set to "Unauthorized". This requires each connection request to be authorized by the user.
  • Do not accept unsigned applications (no digital signature) or applications sent from unknown sources. Be absolutely sure of the origin of the application before accepting it.


Antivirus Protection Dates

  • Initial Rapid Release version January 07, 2005
  • Latest Rapid Release version August 20, 2008 revision 017
  • Initial Daily Certified version January 07, 2005
  • Latest Daily Certified version August 20, 2008 revision 016
  • Initial Weekly Certified release date January 12, 2005

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

Writeup By: Robert X Wang

Discovered: January 05, 2005
Updated: February 13, 2007 12:31:40 PM
Type: Worm
Systems Affected: EPOC


SymbOS.Cabir.O is transmitted through Bluetooth as a .SIS file.

When the worm arrives at a target device the following may happen:

  1. The device displays a message similar to the following, asking the user to accept a message from a particular device:

    Receive message via Bluetooth from [device name]?

  2. The user will be notified that they have received a new message.

  3. The user will be prompted with a message similar to the following:

    Application is untrusted and may have problems. Install only if you trust provider.

  4. If the user chooses Yes, the user will be prompted to install the worm.

    Install mobile?

  5. If the user chooses Install, the worm is installed, executed, and then displays the following message:

    mobile

  6. The worm creates the following files on the phone:

    • \SYSTEM\APPS\mobile\mobile.APP
    • \SYSTEM\APPS\mobile\mobile.RSC
    • \SYSTEM\APPS\mobile\FLO.MDL
    • C:\SYSTEM\SYMBIANSECUREDATA\mobileSECURITYMANAGER\mobile.APP
    • C:\SYSTEM\SYMBIANSECUREDATA\mobileSECURITYMANAGER\mobile.RSC
    • C:\SYSTEM\SYMBIANSECUREDATA\mobileSECURITYMANAGER\mobile.SIS
    • C:\SYSTEM\RECOGS\FLO.MDL
    • C:\SYSTEM\INSTALLS\mobile.SIS

  7. The worm attempts to send itself to other Bluetooth-enabled device that it finds, regardless of the type of device.

  8. The worm executes every time the device is turned on.


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: Robert X Wang

Discovered: January 05, 2005
Updated: February 13, 2007 12:31:40 PM
Type: Worm
Systems Affected: EPOC


To remove SymbOS.Cabir.O:

  1. Install a file manager program on the phone.
  2. Enable the option to view the files in the system directory.
  3. Search the drives, A through Y, for the \SYSTEM\APPS\mobile directory.
  4. Delete the files mobile.app, mobile.rsc, and FLO.MDL from the \mobile directory.
  5. Go to the C:\SYSTEM\SYMBIANSECUREDATA\mobileSECURITYMANAGER directory.
  6. Delete the files mobile.app, mobile.rsc, and mobile.SIS.
  7. Go to the C:\SYSTEM\RECOGS directory.
  8. Delete the file, FLO.MDL.
  9. Go to the C:\SYSTEM\INSTALLS directory.
  10. Delete the file, mobile.SIS.


    Note: You cannot delete the file mobile.rsc when the program is running.

    If you cannot delete this file in steps 4 and 6, delete all the files that you can, restart the phone, and then delete the mobile.rsc file.


Writeup By: Robert X Wang