Horizontal privilege escalation, on the other hand, is simpler since it allows a user to use the same privileges gained from the initial access.
A good example is where an attacker has been able to steal the login credentials of an administrator of a network. The administrator account already has high privileges that the attacker assumes immediately after accessing it.
Horizontal privilege also occurs when an attacker is able to access protected resources using a normal user account. A good example is where a normal user is erroneously able to access the account of another user. This is normally done through session and cookie theft, cross-site scripting, guessing weak passwords, and logging keystrokes.