Threat Descriptions

Trojan:SymbOS/CDropper.A

Classification

Category :

Malware

Type :

Trojan

Platform :

SymbOS

Aliases :

Trojan:SymbOS/CDropper.A, SymbOS/Cabir.Dropper

Summary

Trojan:SymbOS/CDropper.A infects mobile devices that run on the Symbian Series 60 operating system. On arriving on a clean device, it will install Cabir.E and Cabir.D into the device and disables the Bluetooth control application.

Removal

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

The original version of CDropper.A is distributed in a Symbian installation file deceptively named "Norton AntiVirus 2004 Professional.sis". When Cdropper.A is installed, it will drop files into the following directories:

  • \images\
  • \sounds\digital
  • \system\apps
  • \system\install
  • \system\recogs
  • \system\apps\btui
  • \system\apps\fexplorer
  • \system\apps\file
  • \system\apps\freakbtui
  • \system\apps\smartfileman
  • \system\apps\smartmovie
  • \system\apps\systemexplorer
  • \system\apps\[yuan]

Activity

CDropper.A installs different Cabir variants into several places in the device file system.

Some of the installed Cabirs replace common third party applications (FExplorer, SmartFileMan, Smartmovie and SystemExplorer) so that if user has one of those applications installed, it gets replaced with Bluetooth-Worm:SymbOS/Cabir.D and its icon in the menu will go blank.

If user clicks on one of the replaced icons in the menu, the Cabir.D that has replaced that application will start and try to spread to other devices. If Cabir.D starts, it will spread as Cabir.D ([YUAN].SIS) without other Cabir variants or Cdropper.A

CDropper.A will also install auto start component that tries to automatically start Cabir.D upon system reboot, but fails as the auto start component points into directory that is not installed on the device.

CDropper.A will also install non-functional version of the Bluetooth control application, so that user cannot change Bluetooth settings without disinfecting the device first.