title: Reverse Engineer Simple Application with IDA Pro 5
body: <p>This application is the first application challenge on the site hackthissite.org.</p>
  
  <p>The idea is to find the serial. When you enter the serial number and press ok, it pops up a message box with a password for the challenge if correct, or a message saying the serial is wrong.
  To solve the challenge you are supposed to find the password which is in plaintext in the binary at 0x1670FE.</p>
  
  <p>I was trying to find IDA Pro where the string you enter is compared to the serial in the binary.</p>
  
  <p>I want to be able to find where it's compared, be able to change the jump to allow it to accept any wrong password, or change it so it accepts any password.</p>
  
  <p>I can't seem to do this. I've found where the message box is displayed (by searching for Messagebox and adding breakpoints), where it pushes the addresses of the "Sorry" or "Correct" strings on to the stack.</p>
  
  <p>I've tried adding breakpoints on the addresses of these strings and on the Serial itself, but it doesn't seem to work.
  IDA doesn't seem to recognise these as strings, they don't show up in the sting window.</p>
  
  <p>I've also tried to follow this function back but I reach a point where I can't seem to go back any further.</p>
  
  <p>Any help, information, or tips would be greatly appreciated. I really want to know how to figure this kind of problem out.</p>
  
  <p>Sorry if it is a very basic question.</p>
  
  <p>Thanks.</p>