Backdoor.NetDevil

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Discovered: February 13, 2002
Updated: February 13, 2007 11:47:40 AM
Also Known As: Win32.Netdevil
Type: Trojan Horse
Systems Affected: Windows


Backdoor.NetDevil allows a hacker to remotely control an infected computer.



Possible system changes
If the Trojan ran and a hacker executed files on the computer, it may be difficult to determine exactly what was done, even after you remove the Trojan. If you are familiar with your operating system and how to use system repair or system checking tools, we suggest that you fully check the system for any of these modifications and undo them. Otherwise, consider reinstalling Windows.

Antivirus Protection Dates

  • Initial Rapid Release version February 13, 2002
  • Latest Rapid Release version May 24, 2018 revision 049
  • Initial Daily Certified version February 13, 2002 revision 002
  • Latest Daily Certified version May 25, 2018 revision 017
  • Initial Weekly Certified release date February 13, 2002

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Andre Post

Discovered: February 13, 2002
Updated: February 13, 2007 11:47:40 AM
Also Known As: Win32.Netdevil
Type: Trojan Horse
Systems Affected: Windows


When Backdoor.NetDevil runs, it does the following:

It copies itself to the %System% folder. The file name that it uses may vary, because the hacker who creates this backdoor Trojan can choose any desired file name.

NOTE: %System% is a variable. The Trojan locates the \Windows\System folder (by default this is C:\Windows\System or C:\Winnt\System32) and copies itself to that location.

It adds a value that refers to the dropped file to one of the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\Run
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\RunServices

When the hacker creates the BackDoor.NetDevil server file, there are many functions that can be added. For example, the file can be programmed to:

  • Display a fake error message to conceal its true nature.
  • Choose the ports that are used by the backdoor to communicate with the hacker. By default, it uses port 901 for direct control, port 902 for communicating logged keystrokes, and port 903 for file transfer.
  • Use different notification methods to send information to the hacker about the compromised computer.
  • Attempt to kill running firewall and antivirus processes.

When Backdoor.NetDevil runs, it allows the hacker to remotely take control over the compromised computer. This allows the hacker to
  • Obtain full control of the file system
  • Upload files to and download files from the host computer
  • Run files of the hacker's choice
  • Kill running processes
  • Display messages
  • View the contents of the screen
  • Log keystrokes
  • Perform annoying actions, such as manipulating the mouse, opening and closing the CD-ROM drive, turning the monitor on and off, and so on.


Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • 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.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a 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.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. 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.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.

Writeup By: Andre Post

Discovered: February 13, 2002
Updated: February 13, 2007 11:47:40 AM
Also Known As: Win32.Netdevil
Type: Trojan Horse
Systems Affected: Windows


NOTE: These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

  1. Update the virus definitions.
  2. Restart the computer in Safe mode.
  3. Run a full system scan, and delete all files that are detected as Backdoor.NetDevil.
  4. Reverse the changes that the Trojan made to the registry.
For details on how to do this, read the following instructions.

To update the virus definitions:
All virus definitions receive full quality assurance testing by Symantec Security Response before being posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Run LiveUpdate, which is the easiest way to obtain virus definitions. These virus definitions are posted to the LiveUpdate servers one time each week (usually Wednesdays) unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this write-up.
  • Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and installed manually. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this write-up.

    Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.

To restart the computer in Safe mode:
All Windows 32-bit operating systems, except for Windows NT, can be restarted in Safe mode. For instructions on how to do this, read the document How to start the computer in Safe Mode .

To scan for and delete the infected files:
  1. Start your Symantec antivirus program, and make sure that it is configured to scan all files.
  2. Run a full system scan.
  3. If any files are detected as infected with Backdoor.NetDevil, click Delete.

To reverse the changes that the Trojan made to the registry:

CAUTION
: Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify only the keys that are specified. Read the document How to make a backup of the Windows registry for instructions.
  1. Click Start, and click Run. The Run dialog box appears.
  2. Type regedit and then click OK. The Registry Editor opens.
  3. Navigate in turn to each of these keys:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
    CurrentVersion\Run
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
    CurrentVersion\RunServices
  4. In the right pane for each key, delete the value that refers to the file name that was detected as the Trojan.
  5. Exit the Registry Editor.


Writeup By: Andre Post