Class Backdoor
Platform Win32

Technical Details

This Troajn program can be used for remote administration of the victim machine. It has both a client and a server component.

The server component is written in Microsoft Visual C++. It is 28672 bytes in size, and is not packed in any way. The client component is also written in Microsoft Visual C++, and it 32768 bytes in size. It is not packed in any way.


The remote malicious user launches the client component on his/ her machine. This makes it possible to send commands to the server component which is installed on the victim machine. The malicious user has to give the address of the victim machine.

The program contains the following strings:

AckCmd 1.1 – The Ack Command Prompt for Windows 2000

– (c) 2000, **** Vidstrom, ****.vidstrom@****

– For instructions see http://****

The server component makes it possible for the remote malicious user to open the command line on the victim machine and execute commands via the command line on the victim machine.

The interesting feature about this backdoor is that it only uses ACK packets. This means that a standard connection is not established; rather, data will be transmitted directly using ACK packets. This makes it possible for the Trojan to bypass some firewalls.

The backdoor does not have any replication routine.

Removal instructions

  1. Use Task Manager to terminate the Trojan process.
  2. Delete the original backdoor file (its location on the victim machine will depend on how the program originally penetrated the victim machine).
  3. Update your antivirus databases, and perform a full scan of the computer (download a trial version of Kaspersky Anti-Virus).
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