HOW TO CRACK, by +ORC, A TUTORIAL --------------------------------------------------------------------------- Lesson 2: tools and tricks of the trade --------------------------------------------------------------------------- [INDY.EXE] -------------------------------------- LOST IN THE DARK CODEWOODS When you break into a program you end up in portions of code that are unfamiliar to you. It is also not uncommon for the breakpoints to occur outside of the confines of the program you want to crack. Getting your bearings is, in these cases, very important. One of the handiest utilities is the memory dump tool -it tells you where all the device drivers and TSR are loaded, in which memory locations the program you are cracking dwells, how much memory is left and what the next program load point is. The tools you use should report on the following: - the contents of interrupt vectors - the state of the BIOS data area, beginning at address 40:0 - internal structures within DOS, such as the MCB chain, the SFT (System File Table) chain, the chain of installed device drivers, the PSPs and memory allocations associated with installed TSRs - memory allocation statistic from XMS and EMS drivers When seeking to understand a section of foreign code, you must be especially careful to seek the real intent of the code. Consider using a profiler prior to undertaking an analysis of an unfamiliar program. This will help you by ensuring that you don't waste time studying sections of the program that aren't even involved in the protection scheme you are chasing down. Using a utility that charts a program's calling hierarchy can give you an important perspective on how your babe conducts its internal operations. YOUR DEBUGGER: YOUR FAVOURITE TOOL First and foremost, your debugger must be designed for use with resident modules (or must be itself a resident module). Trying to crack with simplistic [debug.com] is a sure way to get absolutely nowhere. We recommend Softice.exe from Nu-Mega technologies (Version 2.6 [S-Ice.exe] has been cracked by MARQUIS DE SOIREE and its vastly available on the Web). You could also use [Periscope] or [Codeview] or Borland's Turbodebugger... all these programs have been boldly cracked and/or distributed and are now on the Web for free... learn how to use YAHOO and find them. In emergency cases you could fix some quick crack using [debug] or [symdeb], but, as said above, most of the time these older debuggers won't do. I'll nevertheless ALWAYS give the final crack procedure for [debug.com], in order to permit even lusers to crack programs. When you first smell a protection, it can be tempting to immediately begin your crack using invasive types of techniques. While there is certainly nothing wrong with this approach, provided that you are fairly familiar with the protection scheme used, going in too deep too soon can be a problem when you don't have a strong hunch. Most of the time you'll end up missing important details. So first of all sit down and ponder... that's the zen-way, the only one that really works. Single-stepping is expensive, not only because of the time it requires but also because of the amount of detail with which you must contend. Your immediate goal is to home in on the protection scheme through a series of successively refined traps, your broader aim is to get an overview idea of the program's action... the wise use of breakpoints will condense these minutiae into an understandable form. The first step is to try to identify the section of the program where the protection scheme is snapping. Once you are able to isolate a certain section of a program, breakpoints can Show More
