SymbOS.Pbstealer.A

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Discovered: November 21, 2005
Updated: February 13, 2007 12:46:42 PM
Also Known As: Pbstealer.A [F-Secure]
Type: Trojan Horse
Systems Affected: EPOC



SymbOS.Pbstealer.A is a Trojan horse that runs on the Symbian OS, which is used as the operating system for Nokia Series 60 cellular telephones. The Trojan sends the user's contact information database to other Bluetooth-enabled devices.

SymbOS.Pbstealer.A reportedly arrives as PBEXPLORER.sis.



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 November 22, 2005
  • Latest Rapid Release version December 22, 2017 revision 021
  • Initial Daily Certified version November 22, 2005
  • Latest Daily Certified version December 23, 2017 revision 007
  • Initial Weekly Certified release date November 23, 2005

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

Writeup By: Kaoru Hayashi

Discovered: November 21, 2005
Updated: February 13, 2007 12:46:42 PM
Also Known As: Pbstealer.A [F-Secure]
Type: Trojan Horse
Systems Affected: EPOC


When SymbOS.Pbstealer.A is executed, it performs the following actions:

  1. Copies itself as the following file:

    PBEXPLORER.sis

    Note: If a user opens this file, the device Installer will display a dialog to warn the user that the application may be coming from an untrusted source and may cause potential problems.

  2. If the user clicks yes, the phone will display a message prompting the user to Install:

    PBEXPLORER



  3. Creates the following files:

    C:\system\apps\pbexplorer\pbexplorer.app
    C:\system\apps\pbexplorer\pbexplorer.rsc
    C:\system\install\pbexplorer.sis

  4. Displays the following message after installation:

    Compacting your contact(s), step2
    Please wait again
    until done...


  5. Copies the contents of the users contact information database to the following file:

    C:\SYSTEM\MAIL\PHONEBOOK.TXT

  6. Scans for Bluetooth-enabled devices. It repeatedly attempts to send the file C:\SYSTEM\MAIL\PHONEBOOK.TXT to the first Bluetooth-enabled device it finds.

  7. Stops trying to send the above file via Bluetooth after one minute and displays the following message:

    Compacting your contact(s), step2
    Done!!!


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: Kaoru Hayashi

Discovered: November 21, 2005
Updated: February 13, 2007 12:46:42 PM
Also Known As: Pbstealer.A [F-Secure]
Type: Trojan Horse
Systems Affected: EPOC


Install a file manager program on the device.

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

  2. Delete the following files:

    C:\system\apps\pbexplorer\pbexplorer.app
    C:\system\apps\pbexplorer\pbexplorer.rsc
    C:\system\install\pbexplorer.sis
  3. Delete the following folder, if it is empty:

    C:\system\apps\pbexplorer

  4. Exit the file manager.


Writeup By: Kaoru Hayashi