Network Security Tools

Compiling and Testing hide_sshd

The hide_sshd.c source code assumes we are trying to hide the presence of sshd running on a host. If you want to hide any other service, change the value of PORT_TO_HIDE. For the purposes of this section, we assume that sshd is running on the host. Make sure by running netstat:

[notroot]$ netstat -na | grep 22
tcp     0     0.0.0.0:22    0.0.0.0:*    LISTEN

Use the following makefile:

obj-m += hide_sshd.o

Compile using the following make command:

[notroot]$ make -C /usr/src/linux-`uname -r` SUBDIRS=$PWD modules

Insert the module:

[root]# insmod ./hide_sshd.ko

Now sshd will not be visible. Try the netstat query again:

[notroot]# netstat -na | grep 22

Unload the module when done:

[root]# rmmod hide_sshd