F-Secure Virus Descriptions : Asylum

NAME:	Asylum
ALIAS:	Backdoor.Asylum

Asylum is a simple backdoor that works on Windows 9x/ME, NT/2000. The backdoor is located in the windows directory and called 'winmp32.exe'. When run it installs itself and sends a notification to the author about the infected machine using ICQ web interface. The service then runs on TCP port 81 and accessible from anywhere if the machine has direct Internet connection.

It supports the following commands:

 - password authentication (required before the other commands)
 - remove the backdoor from the system
 - reboot the machine
 - print Windows directory
 - print Windows system directory
 - upload a file to the machine
 - run a program on the machine

For installation it has many ways of modifying the system. It chooses from them using internal variables set by the author.

It can create keys under

 '[HKLM]\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\SystemAdministration'
 '[HKLM]\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices\SystemAdministration'

Other way is to modify win.ini to look like this:

 [Windows]
 load=winmp32.exe
 run=winmp3.exe

 [boot]
 shell=explorer.exe winmp32.exe

Removal instructions:

- delete the backdoor file from Windows directory - remove the registry and win.ini entries mentioned above

[Analysis: Gergely Erdelyi; F-Secure Corp.; Aug. 24, 2001]