Shellcodes plays a very important role in cyber security field, they are widely used in a lot of malware and exploits. So, what is shellcode? Shellcode is basically a series of bytes that will be interpreted as instructions on CPU, the main purpose of writing shellcodes is exploiting vulnerabilities that allows executing arbitrary bytes on the system such as overflow vulnerabilities also, because of shellcodes can run directly inside memory wast amount of malware takes advantage of it, the reason behind the name shellcode is usually shellcodes returns a command shell when executed but in time the meaning has evolved, today almost all compiler generated programs can be converted to shellcode, because of writing shellcode involves an in-depth understanding of assembly language for the target architecture and operating system, this paper will assume reader knows how to write programs in assembly on both Windows and Linux environments. There are a lot of open source shellcodes on the internet but for exploiting new and different vulnerabilities every cyber security researcher should be able to write his/her own sophisticated shellcode, INVICTUS 5 Security Paper also writing your own shellcodes will help a lot for understanding the key concepts of operating systems, the aim of this paper is explaining basic shellcoding concepts, showing effective methods for decreasing the detection rate on shellcodes and bypassing some anti exploit mitigation.
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