How to hack a firewall using reverse telnet

There are hundreds of legitimate reasons a network administrator would need to remotely execute commands. The following techniques can be used to change server settings, set backups, check security logs or any other task you can do via the command prompt.

This video shows two very simple and well documented tools for remote execution. PSEXEC.EXE and NC.EXE PSEXEC.EXE can be used to set up a PSexec connection and NC.EXE can be used to create a Reverse Telnet connection. Reverse Telnet can connect to a remote system even if the firewall is on with all incoming ports blocked.

You should be aware that even thought these are legitimate tools, most antivirus programs will flag these files because they have been abused in the past. It is important to note that tasklist and taskkill can run on remote systems without PSexec.exe. For more on using reverse telnet to hack a firewall, watch this how-to.