Assuming that I have no ability to use sudo and rather limited permissions, but I have a shell script exploit that allows to me change the file ownership of a file to the current user by running a buggy program written in C that has root permissions. Specifically, the
execlp() function is what is being exploited as I have already found a way to specify the
file parameter. The
user variable is received by a call to the
execlp("chown", user, file, (char *)0);
How would I exploit this ability to gain ownership of any file in the system to ultimately gain sudo access over the system? What files would I modify?
I've tried modifying the etc/sudoers file itself but it would give the following errors
sudo: no valid sudoers sources found, quitting sudo: /etc/sudoers is owned by uid 1000, should be 0
Note that I can't change the file's owner back to root as the current user does not have permission to chown the file to root.
I am operating on a dummy VM right now and this is just a security exercise.
Side note: perhaps that last character array parameter in the code could be exploited somehow too?