Introduction
In Unix-like operating systems, setuid (set user ID) is a special file permission that allows a user to execute a file with the permissions of the file's owner. While this can be useful for certain system operations, it can also pose security risks if misused. In this challenge, you'll learn how to identify and list all setuid files on a system, which is an essential skill for system administrators and security professionals.
Environment
LabEx uses Red Hat Universal Base Image 9 (UBI9) to simulate the exam environment. It may not be identical to the actual RHCSA exam environment, but it provides a good representation of the tasks you'll encounter.
There are two users in the environment:
labex: A standard user with sudo privileges, password:labex.root: The system administrator, password:redhat.
The challenge features real exam questions, along with explanations, requirements, and automated verification scripts to help you confirm task completion. It effectively simulates the knowledge areas covered in the RHCSA exam.
Locate and List Setuid Files
In this step, you'll use the find command to search the entire filesystem for setuid files and save the results to a file.
Tasks
- Search the entire filesystem for files with the setuid permission set.
- Save the list of setuid files to a file named
setuid_listin your home directory.
Requirements
- Execute all commands as the
labexuser in the/home/labexdirectory. - Use the
findcommand to search for setuid files. - Save the output to a file named
setuid_listin the/home/labexdirectory.
Example
After completing this task, the setuid_list file might contain entries similar to the following:
/usr/bin/sudo
/usr/bin/passwd
/usr/bin/chage
/usr/bin/gpasswd
/usr/bin/newgrp
/usr/bin/su
/usr/bin/mount
/usr/bin/umount
/usr/bin/crontab
/usr/bin/pkexec
Note that the actual list may vary depending on the system configuration.
Summary
In this challenge, you learned how to find and list all setuid files on a Unix-like system. This task is crucial for system administrators and security professionals to identify potentially risky files with elevated permissions. You used the find command with specific options to locate files with the setuid bit set and redirected the output to a file for further analysis. This skill is valuable for conducting security audits, identifying potential vulnerabilities, and maintaining system integrity.
