How does a hacker identify a operating system

[Sergeo]

It is quite common now that if you do implement protection application on your computer then definitely your computer will get hacked. But one thing confuses me always that along internet there are tons of computers working. How does a hacker identify which operating system I am using and sent threats related to that. Does this is a bug.

[Milton.J]

The attacker has a variety of method in doing this type of recognition. Frequently, operating system recognition is performed during the preliminary phase of an attack; throughout this phase, the attacker will typically endeavour to map susceptible points of your systems security arrangement, recognize the open ports all the way through port scanning – and this information in sequence will later be used to recognize probable vulnerabilities on your system, by identifying services working on your system and their versions.

[Spyrus]

The operating system on your system is presently running can be distinguished with simplicity, unless you are working a firewall that permits no network packets to arrive at your system. Otherwise, by relating to a variety of ports that might presently be opened on your system (for illustration ports like TCP 21 FTP, TCP 23 TELNET, TCP 25 SMTP, TCP 80 HTTP, TCP 110 POP3) the attacker would locate simple to recognize your operating system through unambiguous protocol analysis.

[Snake08]

Generally the mail servers utilize to welcome the client with a greeting – this type of greeting and previous headers are sent back to the attacker without verification essential, and in several cases they include the name of the submission assigned to the operation service that is being queried, and its description, and consequently it is particularly simple to remotely recognize your operating system in this fashion through basically establishing what would be the operating system that the detected service submission is operating on.

[Zachary]

Formerly the operating system has been recognized productively, and a map of open ports and previous sanctuary problems has been twisted, the attacker can be in motion along at finding and exploiting sanctuary holes in your system. It is therefore significant to identify with that remote recognition of operating system is hazardous, even though simple to execute – not by it but for what comes subsequently. And there is no sanctuary prevention measure that we can utilize in all cases with 100% results.

[Big Fish]

The most excellent method to protect this kind of information in sequence is the leakage is to run a robust firewall and to utilize conciliator servers – but once again these are methods of making it additional complicated for the attacker (which at times pays off) but it does not essentially guarantee that you are prevented, knowing that there are even other additional superior methods of identifying operating system which is working on your system, like TCP-IP stack fingerprinting for illustration, that a well trained attacker can utilize and still achieve the necessary information regarding your system and its operating system.