"BASICS OF ETHICAL HACKING:SERIES #3.3"

Image source:https://pixabay.com/en/hacker-attack-intel-processor-3062252/

Hi friends,I am continuing my post of "BASICS OF ETHICAL HACKING SERIES".
You can read my previous post from this below link:
https://steemit.com/hacking/@danishali22786/basics-of-ethical-hacking-series-1
https://steemit.com/hacking/@danishali22786/basics-of-ethical-hacking-series-2
https://steemit.com/hacking/@danishali22786/basics-of-ethical-hacking-series-3
https://steemit.com/hacking/@danishali22786/basics-of-ethical-hacking-series-3.1
https://steemit.com/hacking/@danishali22786/basics-of-ethical-hacking-series-3.2

As I have explained in previous post there are many topics in FootPrinting,So I am continuing it.

"OS FINGERPRINTING"

Operating System(OS) fingerprinting is the process of learning,wherein one can know which operating system is running on the target computer.This can be used by the curious network administrator when he sees a new device on the network.However,OS fingerprinting is done by an uwarranted party on your network.Just as a bank robber may examine the outside of a bank and watch the arrival and departure of employees before robbing the bank,a hacker typically may perform a reconnaissance process on your network prior to the launch of an attack.

Internet Control Message Protocol(ICMP) is a protocol used to send out error messages across a TCP/IP network.Many people recognize ICMP as the protocol used by the ping utility.ICMP is also used with the standard trace-utility.Besides offering wonderful connectivity tests functionality,ICMP can also be used as part of a reconnaissance scan on a network.
There are four areas that help to determine the Operating System(however,there are other signatures as well that can be used).These signatures are:

1.TTL-why does the operating system set the Time To Live on the outbound packet?

2.Window Size-What does the operating system set the Window size At?

3.DF-Does the operating system set the Don't fragment bit?

4.TOS-Does the operating system set the Type of service,and If so,at what?

Types of Fingerprinting

Active OS Fingerprinting:It is the process of actively determining a target network node's underlying operating system by probing the target host with several data packets,and examining the response received.

Recommended tool:nmap

download:www.nmap.org/download.html

Passive FingerPrinting:It is the process which is based on sniffer traces from a remote system.Instead of actively querying the remote system,all that is needed is to capture packets sent from the remote system.Based on the sniffer traces of these packets,one can determine the operating system of the remote host.Similar to active fingerprinting,passive fingerprinting is based on the principle that every operating system's IP stack has its own idiosyncrasies.By analyzing sniffer traces and identifying these differences,one can determine the operating system of the remote host.

Recommended tool:p0f.

Objectives of writing this post:

My main purpose of writing this post is to inform you all that there is no way to completely protect a network unless one knows what he is up against.Only by knowing how an attack happens,and what all an attacker can do to compromise with a machine,individuals and organisations can properly protect their systems.
Legal issues:
I request to all readers to follow legal procedures under all circumstances because you are hacking in to a system.
The government has made it mandatory to get prior permission before running any of the tools against any network.
There are many cyber laws made by the government,we must follow that otherwise It will be considered as a crime.
I have only basic information of ethical hacking learned from internet and by reading various books but I also want to learn it deeply.I want to join some big organization of ethical hacking institutes.But they are very costly.So I am finding a way to earn money and when I have enough money I will take admission to that ethical hacking institutes.
Thank you friends. If you like my post Please