Remote exploits and vulnerabilities category

A "remote exploit" works over a network and exploits the security vulnerability without any prior access to the vulnerable system.

Local exploits and vulnerabilities category

A "local exploit" requires prior access to the vulnerable system and usually increases the privileges of the person running the exploit past those granted by the system administrator. Exploits against client applications also exist, usually consisting of modified servers that send an exploit if accessed with client application.

Shellcode category

In computer security, a shellcode is a small piece of code used as the payload in the exploitation of a software vulnerability. It is called "shellcode" because it typically starts a command shell from which the attacker can control the compromised machine, but any piece of code that performs a similar task can be called shellcode. Because the function of a payload is not limited to merely spawning a shell, some have suggested that the name shellcode is insufficient. Shellcode is commonly written in machine code.

Classification:
There are several methods of classifying exploits. The most common is by how the exploit contacts the vulnerable software. A remote exploit works over a network and exploits the security vulnerability without any prior access to the vulnerable system. A local exploit requires prior access to the vulnerable system and usually increases the privileges of the person running the exploit past those granted by the system administrator. Exploits against client applications also exist, usually consisting of modified servers that send an exploit if accessed with a client application. Exploits against client applications may also require some interaction with the user and thus may be used in combination with the social engineering method. Another classification is by the action against the vulnerable system; unauthorized data access, arbitrary code execution, and denial of service are examples. Many exploits are designed to provide superuser-level access to a computer system. However, it is also possible to use several exploits, first to gain low-level access, then to escalate privileges repeatedly until one reaches root. Normally a single exploit can only take advantage of a specific software vulnerability. Often, when an exploit is published, the vulnerability is fixed through a patch and the exploit becomes obsolete until newer versions of the software become available Shellcodes any types.