Trojan-Dropper.VBS.Asylum

Class Trojan-Dropper
Platform VBS
Description

Technical Details

This Trojan is designed to install other Trojan programs to the victim machine without the knowledge or consent of the user. It is written in Visual Basic Script. The file is 10 796 bytes in size.

Payload

When launching, the Trojan unpacks the following file from itself and launches it for execution:

%windir%server.exe

This file is 16,384 bytes in size, and will be detected by Kaspersky Anti-Virus as Backdoor.Win32.Asylum.013

The Trojan also modifies registry values, resulting in HTA file extensions being hidden, and the icon for My Network Places being changed.

[HKCRhtafile]
NeverShowExt = ""

[HKCRhtafileDefaultIcon]
("Default") = "SHELL32.DLL,17"

The Trojan will delete %startup%winipc32.hta.

It writes startup code for %windir%server.exe to %windir%wininit.ini.

Removal instructions

If your computer does not have an up-to-date antivirus, or does not have an antivirus solution at all, follow the instructions below to delete the malicious program:

  1. Delete the original Trojan file (the location will depend on how the program originally penetrated the victim machine).
  2. Delete the following files:
    %windir%server.exe
  3. Delete the following registry key:
    [HKCRhtafile]
    NeverShowExt = ""
  4. Modify the system registry key value to:
    [HKCRhtafileDefaultIcon]
    (Default) = "%SystemRoot%system32mshta.exe,1"
  5. Update your antivirus databases and perform a full scan of the computer (download a trial version of Kaspersky Anti-Virus).