This is an extra credit assignment with one part. It is due by 5/14/19 at 11:59PM.
There will be no late submissions accepted!
The binary locker requires a flag to be entered. Find the flag, and
prove that it works. Run ./locker <flag> and type echo $?, and take a
screenshot as proof. echo $? prints the exit code of the last running program,
and a working flag should print 0. Any other flag will cause locker to return
-1 (or 255). The flag follows the standard format of CMSC389R-{...}.
Along with the flag, document the steps you took to analyze the binary. What did you do first? What second? Which tools did you use, and which ones were the most or least helpful? Anything you found straight forward? Anything catch you off-guard? These are just examples of some questions that may help you guide your documentation, but it is not an exhaustive list. A fellow classmate familiar with x86-64 assembly should be able to read this reflection and know exactly what to do to solve the binary. Any notes, typed or handwritten, can be pushed to your git repo and embedded in your writeup to help supplement your analysis and explanation.
Full points will be granted with the correct flag, screenshot, and reflection.
If submitted, the grade for this assignment can used to replace the lowest grade for any previous assignment.
Look at the Binaries I and Binaries II slides for guidance.
IDA Pro's Quick Reference
Sheet
may come in handy. The hotkeys N to rename, ; to write line comments, and
Insert to write block comments may be the most useful. Right clicking on
immediate values and selecting "Manual..." may help with representing numerical
data in more useful ways.
If there's an assembly instruction that wasn't covered in the lecture slides, don't worry! There's way too many instructions that can be run on Intel CPUs to fit in a lecture, many of which aren't used that often. You can look up what an instruction does here. Posting on Piazza for help is fine too!
A specific tool reviewed in class probably won't work when analyzing this binary.