Class 15: Our first Write-What-Where

I'll use my Daily PWN to teach this. We will do GOTMilk from the Hero track.

The concept is:

• Find which value of X (an integer) shows your payload via "%X$p"
• Decide where you want to write and make your payload start with that, e.g. p32(target)
• Decide what you want to write there and make the spacing WIDTH minus 4 or 8 (for the size of writing the target)
• Decide how many bytes you are writing (%n, %hn, %hhn, %ln)
• Payload: so if offset was 7 and desired width was 1234 and 32-bit binary and want to write 2 bytes to target then payload is p32(target)+"%1230x%7$hn"