Reversing

Level 6 on the Smash The Stack IO wargame takes two command-line arguments (username and password) and prints a greeting: level6@io:/levels$ ./level06 user pass Hi user Notice that the application checks the LANG environment variable to determine which greeting to print: level6@io:/levels$ export LANG=fr level6@io:/levels$ ./level06 user pass Bienvenue user level6@io:/levels$ export LANG=de level6@io:/levels$ ./level06 user pass Willkommen user Vulnerability Analysis The program structure internally organizes credentials into a record: ...

In this challenge on the Smash The Stack IO wargame, the binaries are located under /levels. Let’s inspect the target binary for Level 1: level1@io:/levels$ ls -alh level01 -r-sr-x--- 1 level2 level1 1.2K Jan 13 2014 level01 Notice the permissions: -r-sr-x--- with the SUID bit set for level2. Executing this binary successfully will spawn a process with level2 privileges. Initial Execution Running the program prompts for a passcode: level1@io:/levels$ ./level01 Enter the 3 digit passcode to enter: 838 Providing an arbitrary number exits silently with no output. ...