SymbOS.Drever.D

SUMMARY

SymbOS.Drever.D is a Trojan horse that disables Simworks Symbian Anti-Virus software.

Behavior

Symptoms

Transmission

Protection

• Virus Definitions (LiveUpdate™ Weekly) November 30, 2005
• Virus Definitions (Intelligent Updater) November 28, 2005

Threat Assessment

Wild

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

Damage

• Damage Level: Low

Distribution

• Distribution Level: Low
• Target of Infection: Nokia 60 series cellular phones

TECHNICAL DETAILS

SymbOS.Drever.D may arrive as a file named:

Drever.sis.

When user clicks on the .sis, the phone will display a dialog to warn users that the application may be coming from an untrusted source and may cause potential problems.



If user clicks yes, the phone will displays a message prompting the user to Install:

"Drever"


When SymbOS.Drever.D is executed, it performs the following action:

1. Drops the following files onto the compromised device. This prevents the Simworks Symbian Anti-Virus software from running when the device is started:
   
   
   • systemappsAntiVirusAVBoot.mdl
   • systemappsAntiVirusAntiVirus.rsc
   • systemappsAntiVirusAntiVirus.app
   • systemappsAntiVirusAntiVirus.aif
     
     
2. Displays the following message after installation:
   
   
   
   
3. The following file is also created:
   
   systeminstallDrever.sis
   
   NOTE: This file is actually created by the Installer, not the threat.
   

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

1. Install a file manager program on the device.
   
   
2. Enable the option to view the files in the system folder.
   
   
3. Delete the following malicious file:
   
   Drever.sis.
   
   
4. Navigate to and delete the following file:
   
   systeminstallDrever.sis
   
   
5. Navigate to the following folder:
   
   
   systemappsAntiVirus
   
   
6. Delete the following files if the phone is infected with SymbOS.Drever.D:
   
   
   • AVBoot.mdl
   • AntiVirus.rsc
   • AntiVirus.app
   • AntiVirus.aif
     
     
7. Exit the file manager.
   
   
8. Reinstall Simworks Symbian Anti-Virus software if the phone is infected with SymbOS.Drever.D.