$7.$ Obtain the ile mystery.zip from the textbook website and extract the executable mystery.exe.

a$)$ Give the output when you run the program with each of the following usernames $($assuming an incorrect serial number$)$:

i$)$ mark

ii$)$ markstamp iii$)$ markkram

b$)$ Analyze the code to determine all restrictions, if any, on valid usernames. You will need to disassemble and debug the code.

c$)$ This program uses IsDebuggerPresent to check for the presence of a debugger. Analyze the code to determine what the program does in case a debugger is detected. Why is this better than simply terminating the program?

d$)$ Patch the program so that you can debug it$.$ You will need to nullify the effect of IsDebuggerPresent.

e$)$ By debugging the code, determine the corresponding valid serial number for each valid username that appears in part a$).$ Hint: Debug the program and enter a username along with any serial number. At some point, the program will compute the valid serial number corresponding to the entered username$$ it uses this to compare to the entered serial number. If you set a breakpoint at the proper location, the valid serial number will be stored in a register, which you can then observe.

f $)$ Create a patched version of the code, mysteryPatch.exe that accepts any username and serial number pair.