After discovering a vulnerability in the passwd utility, the Linux developers have decided that it is too dangerous to continue to run the utility as root (through setuid). Unfortunately, there's no Linux capability that lets a process specifically edit /etc/shadow, the file that Linux uses to store password data. Note: This problem incorrectly stated /etc/passwd instead of /etc/shadow when released. UNIX originally stored password data in /etc/passwd but this was later changed to /etc/shadow. The high-level idea of your solution should not change and we'll accept answers assuming password data is stored in /etc/passwd or /etc/shadow. What's the worst damage that an attacker can do if a new vulnerability were to be found in passwd? [10 points]