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Overview For our example, we use our own program, called serial.exe. This program was written in Visual C++ to provide you with a real working product on which to test and practice your newly acquired knowledge. Our program simulates a simple serial number check that imitates those of many professional programs. You will see firsthand how a cracker can reverse engineer a program to allow any serial number, regardless of length or value. To obtain this embedded crackme, please download serial.exe from.

Figure 4-13. serial.exe Once the program is open, drill down to a point in the program where you can monitor what is happening. As previously discussed, there are several function calls that flag an event worth inspection. For example, using the Names window, we can locate a wcscmp call, which is probably used to validate the entered serial number with the corrected serial number. Using this functions XREF, we can easily locate the chunk of code illustrated in.

Since serial.exe is a relatively simple program, all the code we need to review and play with is located within a few lines. Debugging serial.exe As we illustrated when debugging test.exe, the MVT is a very useful tool that can help a debugger, or a cracker, work through a program's execution line by line. This type of intimate relationship allows an in-depth look at the values being processed and can also allow on-the-fly alteration of data that is stored in the registers, flags, and memory. After the program is loaded, set a breakpoint at 0x00011280, with any changes as defined by the absolute memory block. Once the breakpoint is entered, hit the F5 key to execute the program. You should now see a Serial screen on your Pocket PC as in.

201 rows Html Executable 4.9 Serial Numbers. Convert Html Executable 4.9 trail version to full software. Html Executable Crack Serial Key. This sample system only uses four bytes for key verification. Don't ask me for serial keys or a copy of the game.

Enter any value in the text box and hit the Submit button. Endnote Crack 8.0.2 there. Step-Through Investigation At this point, serial.exe is loaded on the Pocket PC and the MVT is paused at a breakpoint. The next command the processor executes MOV R1, #1. This is a simple command to move the value 1 into register 1 (R1).

Before executing this line, look at the Registers window and note the value of R1. You should also note that all the register values are red; this is because they have all changed from the last time the program was paused. Now, hit the F11 key to execute the next line of code. After a short pause, the MVT returns to pause mode, at which time you should notice several things. The first is that most of the register values turned to black, which means they did not change values. The second is that R1 now equals 1. The next line loads the R0 register with the value in R4.

Once again, hit the F11 key to let the program execute this line of code. After a brief pause, you will see that R0 is equal to R4. Step through a few more lines of code until your yellow arrow is at address 0x00011290. At this point, let's take a look at the Registers window. The last line of code executed was an LDR command that loaded a value (or address representing the value) from memory into a register. In this case, the value was loaded into R1, which should be equal to 0006501C.

Locate the Memory window and enter the address stored by R1 into the 'Address:' box. Once you hit Enter, you should see the serial number you entered. Armitron Pro Sport Watch User Manual. After executing the next line, we can see that R0 is given a small integer value.