SymbOS.Cabir

SUMMARY

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

This 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.

Behavior

Symptoms

Transmission

Protection

• Virus Definitions (LiveUpdate™ Weekly) June 16, 2004
• Virus Definitions (Intelligent Updater) June 15, 2004

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Low
• Degrades Performance: Scanning for Bluetooth devices may impact the overall performance of the device.

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

SymbOS.Cabir 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 caribe?
   
   
5. If the user chooses Install, SymbOS.Cabir is installed and executed, displaying the message:
   
   Caribe-VZ/29a
   
   
   
   
6. The worm creates the following files on the phone:
   
   
   • SYSTEMAPPSCARIBECARIBE.APP
   • SYSTEMAPPSCARIBECARIBE.RSC
   • SYSTEMAPPSCARIBEFLO.MDL
   • C:SYSTEMSYMBIANSECUREDATACARIBESECURITYMANAGERCARIBE.APP
   • C:SYSTEMSYMBIANSECUREDATACARIBESECURITYMANAGERCARIBE.RSC
   • C:SYSTEMSYMBIANSECUREDATACARIBESECURITYMANAGERCARIBE.SIS
   • C:SYSTEMRECOGSFLO.MDL
   • C:SYSTEMINSTALLSCARIBE.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":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

Removal using the Symantec Mobile Threats Removal Tool
Symantec Security Response has developed a removal tool to clean the infections of SymbOS.Cabir. Use this removal tool first, as it is the easiest way to remove this threat.

Manual Removal:
To remove SymbOS.Cabir:

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 SYSTEMAPPSCARIBE directory.
4. Delete the files CARIBE.APP, CARIBE.RSC, and FLO.MDL from the CARIBE directory.
5. Go to the C:SYSTEMSYMBIANSECUREDATACARIBESECURITYMANAGER directory.
6. Delete the files CARIBE.APP, CARIBE.RSC, and CARIBE.SIS.
7. Go to the C:SYSTEMRECOGS directory.
8. Delete the file, FLO.MDL.
9. Go to the C:SYSTEMINSTALLS directory.
10. Delete the file, CARIBE.SIS.
    
    Note: You cannot delete the file CARIBE.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 CARIBE.RSC file.