icmpsh is a simple reverse ICMP shell with a win32 slave and a POSIX compatible master in C, Perl or Python. The main advantage over the other similar open source tools is that it does not require administrative privileges to run on the target machine.

The tool is clean, easy and portable. The slave (client) runs on the target Windows machine, it is written in C and works on Windows only whereas the master (server) can run on any platform on the attacker machine.

Running the master:

The master is straight forward to use. There are no extra libraries required for the C and Python versions. The Perl master however has the following dependencies:

• IO::Socket
• NetPacket::IP
• NetPacket::ICMP

When running the master, don't forget to disable ICMP replies by the OS. For example:

sysctl -w net.ipv4.icmp_echo_ignore_all=1

Running the slave:
The slave comes with a few command line options as outlined below:

-t host            host ip address to send ping requests to. This option is mandatory!
 
 -r                 send a single test icmp request containing the string "Test1234" 
                    and then quit. This is for testing the connection.
 
 -d milliseconds    delay between requests in milliseconds 
 
 -o milliseconds    timeout of responses in milliseconds. If a response has not received 
                    in time, the slave will increase a counter of blanks. If that counter 
                    reaches a limit, the slave will quit. The counter is set back to 0 if 
                    a response was received.
 
 -b num             limit of blanks (unanswered icmp requests before quitting)
 
 -s bytes           maximal data buffer size in bytes