Day 10: Advanced Privilege Escalation & Security Audits 🕵️‍♂️

Day 10 of my #1HourADayJourney. Today was all about breaking things to learn how they are built. If you want to secure a system, you have to think like an attacker. We explored the "hidden" ways a regular user can jump to root.

🛠️ The Security Auditor's Toolkit

Today, I audited a system for common vulnerabilities. Here is what I learned:

1. The SUID Danger Zone

SUID (Set User ID) allows a program to run with the privileges of the file owner.

• The Vulnerability: If a binary is owned by root and has the s bit set, it runs as root. If it's a shell, you get a root shell.
• The Lesson: Always check for binaries with s permissions during your system audit.

2. Cron-based Escalation

One of the most dangerous patterns I found:

• The Scenario: A script owned by root is executable by a group I'm in, or writable by me.
• The Exploit: I can inject a payload into the script, wait for the cron daemon to trigger it as root, and spawn a privileged shell (/bin/bash -p).

3. PATH Hijacking

If a cron job calls backup.sh instead of /usr/local/bin/backup.sh, the system searches the $PATH. If I control a directory earlier in the path, I can place my own backup.sh there.

• Rule of thumb: Always use full, absolute paths in cron jobs and configuration files.

The takeaway: Security is a chain. If one link—like a single writable script in a cron job—is weak, the whole fortress falls.

Follow my journey: #1HourADayJourney