Structured exception handling (SEH) is an exception handling mechanism included in most programs to make them robust and reliable. It is used to handle many types of errors and any exceptions that arise during the normal execution of an application. SEH exploits happen when the exception handler of an application is manipulated, causing it to force an application to close. Hackers normally attack the logic of the SEH, causing it to correct nonexistent errors and lead a system to a graceful shutdown. This technique is sometimes used with buffer overflows to ensure that a system brought down by overflows is closed to prevent unnecessary and excessive damage.

In the following section we will discuss some of the common ways that hackers compromise systems. More focus will be laid on how to compromise Windows operating systems using Linux-based tools, since most computers and a significant percentage of servers run on Windows. The attacks discussed will be launched from BackTrack 5, a Linux distribution that is focused on security. The same distribution is what hackers and penetration testers commonly use to compromise systems. Some of the tools that will be covered have been discussed in the previous chapter.