Privilege Escalation: When Attackers Climb the Access Ladder
Privilege escalation is a security attack where a user gains access beyond their authorization — vertical (user→admin) or horizontal (user→other user) — a fundamental vulnerability class.
Privilege escalation is a security attack where an attacker gains access levels beyond their authorization. It comes in two forms: - **Vertical escalation**: Moving up the privilege hierarchy (normal user → root/admin). The more dangerous variant — full system compromise. - **Horizontal escalation**: Accessing peer accounts without authorization (user A accessing user B's data). Common in multi-tenant web applications. ## Common Vectors - Misconfigured sudo rules or SUID binaries on Linux - Kernel exploits that bypass OS permission checks - Token theft or session hijacking - Insecure direct object references (IDOR) in web apps - Credential reuse from compromised databases - Container escape (breaking out of Docker/VM isolation) ## Why It Matters Privilege escalation is often the second step in an attack chain: initial access via phishing or a web vulnerability provides a foothold, then escalation converts that foothold into full control. Salt Typhoon SD-WAN Attack: Zero-Day Plus Firmware Downgrade Chain by Chinese State APT demonstrated privilege escalation via firmware downgrade. Defense-in-depth strategies include the principle of least privilege, regular patching, separation of duties, and monitoring for anomalous privilege use.