Question 1

What is privilege escalation?

Accepted Answer

Privilege escalation is when an attacker gains higher access levels than originally authorized — typically moving from a standard user to administrator or root. Vertical escalation means gaining higher privileges, while horizontal escalation means accessing another user's resources at the same privilege level. Common vectors include SUID binaries, misconfigured sudo rules, writable cron jobs, kernel exploits, and weak file permissions.

Question 2

How do I defend against privilege escalation on Linux systems?

Accepted Answer

Regularly audit SUID/SGID binaries and remove unnecessary ones. Follow the principle of least privilege for sudo configurations. Keep the kernel and all packages updated. Use mandatory access controls like SELinux or AppArmor. Monitor for unusual process execution and privilege changes. Disable unused services, restrict cron job permissions, and ensure sensitive files have proper ownership and permissions.

Privilege Escalation

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