“Nmap can dust for OS fingerprints. Here’s how to disguise
your systems.“
“When someone with half a clue decides to attack your system, he
or she will first try to identify the operating system. Not every
attack proceeds this way: Script kiddies probe huge address spaces
looking for any system with a particular port open, which indicates
that just maybe that system will be vulnerable. But for the
professional penetration tester or hacker, identifying the
operating system is an essential step in probing….”
“The king of stack fingerprinting programs today is Network Map,
or nmap. The author of the nmap program, who goes by the name
Fyodor, has written a paper on the subject, in which he discusses
TCP options and their usefulness in identifying operating systems
via stack fingerprinting (see Resources). This column goes deeper
into TCP options and how they are used by TCP/IP and nmap.”