Glossary
Privilege Escalation
A technique by which an attacker moves from a limited access level to higher rights (administrator, root, domain controller). Vertical escalation targets higher privileges; horizontal escalation targets access to other same-level users' data. It is a key step in nearly every full compromise.
Vertical and horizontal escalation
Vertical escalation means gaining higher rights: from a user account to an administrator, from a container to the host, from a low-privileged AD user to a domain controller. Horizontal escalation stays at the same privilege level but crosses the boundary between users — accessing another user's account or data. In an HR SaaS, horizontal escalation (viewing another employee's or company's payslips) is often as serious as vertical.
Limiting escalation by design
Least privilege remains the best defense: every account, service, and token should hold only the rights strictly required. Add role separation, tenant isolation at the database level (RLS), and regular review of accumulated permissions. A real-world audit deliberately attempts these escalations to measure how far a modest initial access can reach.
Frequently asked questions
What's the difference between vertical and horizontal escalation?
Vertical escalation raises the privilege level (user to administrator). Horizontal escalation keeps the same level but grants access to another user's or tenant's resources. Both are critical in a multi-tenant application.
How do you reduce the risk of privilege escalation?
By applying least privilege everywhere, isolating data per tenant, separating roles, and regularly reviewing accumulated rights. Actively testing escalation paths during an audit reveals the flaws before an attacker exploits them.