Backdoor.Brador.A

SUMMARY

Backdoor.Brador.A is the first Windows Mobile backdoor Trojan horse. This backdoor sends the IP address of the infected handheld to the attacker and opens TCP port 2989.

Backdoor.Brador.A will work on Windows Mobile 2003 and only affects ARM-based devices.

Note: Windows Mobile 2003 is also known as Pocket PC 2003 and Windows CE 4.2.

Protection

• Virus Definitions (LiveUpdate™ Weekly) August 9, 2004
• Virus Definitions (Intelligent Updater) August 5, 2004

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
• Compromises Security Settings: Sends the attacker the IP address of the infected handheld.

Distribution

• Distribution Level: Low
• Ports: TCP port 2989

TECHNICAL DETAILS

When Backdoor.Brador.A is launched, it performs the following actions:

1. Copies itself to Windows/StartUp/Svchost.exe (5632 bytes) so that it starts when Windows starts.
   
   
2. Continually attempts to send the attacker the IP address of the handheld by email until it succeeds.
   
   
3. Opens TCP port 2989 and waits for further instructions from the attacker.
   
   
4. Allows the attacker to remotely perform the following commands:
   
   • List the directory contents
   • Upload a file
   • Display a message box
   • Download a file
   • Execute the specified command

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

The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Update the virus definitions.
2. Run a full system scan and delete all the files detected as Backdoor.Brador.A.

For specific details on each of these steps, read the following instructions.

1. To update the virus definitions
Run LiveUpdate to obtain the latest virus definitions for Symantec AntiVirus for Handhelds. For instructions on how to do this, read the document, "Updating virus definitions for Symantec AntiVirus for Handhelds Corporate Edition 3.2."

2. To scan for and delete the infected files

1. Start Symantec AntiVirus for Handhelds and make sure that it is configured to scan the main storage and mounted file systems.
2. Run a scan.
3. If any files are detected as infected with Backdoor.Brador.A, delete them.