Today, we look more in depth into nmap, a popular open-source security
scanner. We are interested in analyzing the accuracy of nmap, as well as
the network footprint seen when using some of its more popular scripts.
To begin we create a network of six Virtual-Box machines which consist of
three Metasploitable Linux, one Kali Linux, one Ubuntu 14.04, and one
Centos 7 machines. We find the banner information gathered from a nmap
scan to be accurate if a machine’s security is not properly configured.
Using Wireshark we analyze the amount of packets sent during a full version
scan to be 182 KB over 123.54 seconds or 1.47 KB/sec. Next we use a Python
program to exploit the Simple Mail Transfer Protocol (SMTP) to gather a
list of known users on a server. We have success in validity emails on our
Metasploitable virtual machine.