COMMON WEAKNESS ENUMERATIONIncomplete

CWE-284

Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Abstraction

Pillar

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Extended description

Access control involves the use of several protection mechanisms such as: - Authentication (proving the identity of an actor) - Authorization (ensuring that a given actor can access a resource), and - Accountability (tracking of activities that were performed) When any mechanism is not applied or otherwise fails, attackers can compromise the security of the product by gaining privileges, reading sensitive information, executing commands, evading detection, etc. There are two distinct behaviors that can introduce access control weaknesses: - Specification: incorrect privileges, permissions, ownership, etc. are explicitly specified for either the user or the resource (for example, setting a password file to be world-writable, or giving administrator capabilities to a guest user). This action could be performed by the program or the administrator. - Enforcement: the mechanism contains errors that prevent it from properly enforcing the specified access control requirements (e.g., allowing the user to specify their own privileges, or allowing a syntactically-incorrect ACL to produce insecure settings). This problem occurs within the program itself, in that it does not actually enforce the intended security policy that the administrator specifies.

Terminology

Alternate terms and usages

Authorization

The terms "access control" and "authorization" are often used interchangeably, although many people have distinct definitions. The CWE usage of "access control" is intended as a general term for the various mechanisms that restrict which users can access which resources, and "authorization" is more narrowly defined. It is unlikely that there will be community consensus on the use of these terms.

Root cause

How and when does the problem arise?

Lifecycle phase

Architecture and Design

Lifecycle phase

Implementation

REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Lifecycle phase

Operation

Risk

What does successful exploitation lead to?

Varies by Context

Affected security scopes: Other

Defence

How is it prevented and fixed?

Architecture and Design · Operation

Defence to apply across several lifecycle phases

Detail
Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.

Architecture and Design

Separation of Privilege

Detail
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.