Threat description




Worm:SymbOS/Mabir.A is a worm that infects devices running the Symbian Series 60 operating system. Mabir.A is capable of spreading in an infected symbian Installation (SIS) file over both Bluetooth and MMS.


Automatic action

F-Secure Mobile Security detects Mabir.A and delete the worm components.


More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.

You may also refer to the Knowledge Base on the F-Secure Community site for more assistance.


After disinfecting the phone, remove the remaining empty directories by going to the Application Manager and uninstalling the SIS file in which Mabir.A arrived (either caribe.sis or info.sis)

Alternative Installation of F-Secure Mobile Anti-Virus and Disinfection

If your phone is infected with Mabir.A and you cannot install files over bluetooth, you can download F-Secure Mobile Anti-Virus directly to your phone:

  • 1. Open web browser on the phone
  • 2. Go to https://mobile.f-secure.com
  • 3. Select link "Download F-Secure Mobile Anti-Virus" and then select phone model
  • 4. Download the file and select open after download
  • 5. Install F-Secure Mobile Anti-Virus
  • 6. Go to applications menu and start Anti-Virus
  • 7. Activate Anti-Virus and scan all files

Technical Details

The SIS file that Mabir.A sends use the file name "caribe.sis". Please note that though Mabir.A uses the same SIS file name as Cabir worms, it is actually different worm.


On receiving the transmitted SIS file, it is automatically installed.

During installation, the installer will copy the worm executables into following locations:

  • \system\apps\Caribe\Caribe.app
  • \system\apps\Caribe\Caribe.rsc
  • \system\apps\Caribe\flo.mdl

When the Mabir.exe is executed it copies the following files:

  • \system\symbiansecuredata\caribesecuritymanager\Caribe.app
  • \system\symbiansecuredata\caribesecuritymanager\Caribe.rsc

And rebuilds its SIS file to:

  • \system\symbiansecuredata\caribesecuritymanager\Info.sis
Replication (Bluetooth)

When Mabir worm is activated on an infected device, it uses the native Bluetooth functionality to start looking for other discoverable Bluetooth-enabled devices. If found, it transmits an infected SIS file to the targetted device. If the target goes out of range or rejects file transfer, Mabir will continue trying to communicate with the same device.

The infected SIS file is always named caribe.sis. To be infected, a user must selected 'Yes' when prompted to do so.

The file contains the worm component files caribe.app, caribe.rsc and flo.mdl. It also contains autostart settings that will automatically execute caribe.app after the SIS file is being installed, thus starting the worm.

Replication (MMS)

MMS messages are multimedia messages that are intended to contain only media content, such as pictures, audio or video, but can also be used to transmit infected Symbian installation files.

The MMS sending is triggered by MMS or SMS message that arrives to the phone, causing Mabir to send itself as MMS message to the number from which the message arrived from. Thus the Mabir tries to fool the receiver that it has been sent as reply to the message that user sent to the infected phone.

The Mabir worm does not use any texts in the MMS messages it sends.

When the recipient opens the MMS message containing the infected SIS file, the action automatically executes the file and causes it to install.

Submit a Sample

Suspect a file or URL was wrongly detected? Send it to our Labs for further analysis

Submit a Sample

Protect your life on every device

F-Secure SAFE looks out for you and the people close to you, on every device

More Info