A shellcode is a group of instructions which can be executed while another program is running. Nowadays lots of examples show how a shellcode can be executed while an application is running and its followings is proposed us by vulnerabilities' exploits.
In order to get advantage from a vulnerability it is indispensable to inject a shellcode because we have to get the control of a running application.

The goal of this article is not to explain all the possibilities of injecting a shellcode developed during last years, but to analyze and understand its essence.

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