What does a horizontal privilege escalation attack involve?

A horizontal privilege escalation attack involves gaining access to resources or functionalities that exist at the same access level as the attacker’s current permissions. This means that the attacker does not increase their access rights but instead exploits the system to access the same type of accounts or resources that should be restricted to others at the same privilege level.

For example, if a user account with limited privileges exploits an application flaw to access another user's files or data under the same permissions, this represents a horizontal escalation. This type of attack typically occurs in multi-user environments where users might have the same level of access but different data or resources. Understanding this concept is crucial in recognizing the security vulnerabilities within systems that could lead to unauthorized data access by users sharing the same access permissions.