COMMON WEAKNESS ENUMERATIONIncomplete

CWE-863

Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Abstraction

Class

Structure

Simple

Likelihood of Exploit

High

Understand the problem

What is the problem?

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Terminology

Alternate terms and usages

AuthZ

"AuthZ" is typically used as an abbreviation of "authorization" within the web application security community. It is distinct from "AuthN" (or, sometimes, "AuthC") which is an abbreviation of "authentication." The use of "Auth" as an abbreviation is discouraged, since it could be used for either authentication or authorization.

Root cause

How and when does the problem arise?

Lifecycle phase

Architecture and Design

Authorization weaknesses may arise when a single-user application is ported to a multi-user environment.

Lifecycle phase

Implementation

REALIZATION: This weakness is caused during implementation of an architectural security tactic. A developer may introduce authorization weaknesses because of a lack of understanding about the underlying technologies. For example, a developer may assume that attackers cannot modify certain inputs such as headers or cookies.

Lifecycle phase

Operation

An access control list (ACL) represents who/what has permissions to a given object. Different operating systems implement (ACLs) in different ways. In UNIX, there are three types of permissions: read, write, and execute. Users are divided into three classes for file access: owner, group owner, and all other users where each class has a separate set of rights. In Windows NT, there are four basic types of permissions for files: "No access", "Read access", "Change access", and "Full control". Windows NT extends the concept of three types of users in UNIX to include a list of users and groups along with their associated permissions. A user can create an object (file) and assign specified permissions to that object.

Risk

What does successful exploitation lead to?

Read Application DataRead Files or Directories

Affected security scopes: Confidentiality

An attacker could bypass intended access restrictions to read sensitive data, either by reading the data directly from a data store that is not correctly restricted, or by accessing insufficiently-protected, privileged functionality to read the data.
Modify Application DataModify Files or Directories

Affected security scopes: Integrity

An attacker could bypass intended access restrictions to modify sensitive data, either by writing the data directly to a data store that is not correctly restricted, or by accessing insufficiently-protected, privileged functionality to write the data.
Gain Privileges or Assume IdentityBypass Protection Mechanism

Affected security scopes: Access Control

An attacker could bypass intended access restrictions to gain privileges by modifying or reading critical data directly, or by accessing privileged functionality.
Execute Unauthorized Code or Commands

Affected security scopes: Confidentiality, Integrity, Availability

An attacker could use elevated privileges to execute unauthorized commands or code.
DoS: Crash, Exit, or RestartDoS: Resource Consumption (CPU)DoS: Resource Consumption (Memory)DoS: Resource Consumption (Other)

Affected security scopes: Availability

An attacker could gain unauthorized access to resources on the system and excessively consume those resources, leading to a denial of service.

Defence

How is it prevented and fixed?

Architecture and Design

Architecture and design approach

Detail
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.

Architecture and Design

Architecture and design approach

Detail
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].

Architecture and Design

Libraries or Frameworks

Detail
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].

Architecture and Design

Architecture and design approach

Detail
For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.

System Configuration · Installation

Defence to apply across several lifecycle phases

Detail
Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

Verification

How is it detected?

Automated Static Analysis

Limited
Automated static analysis is useful for detecting commonly-used idioms for authorization. A tool may be able to analyze related configuration files, such as .htaccess in Apache web servers, or detect the usage of commonly-used authorization libraries. Generally, automated static analysis tools have difficulty detecting custom authorization schemes. Even if they can be customized to recognize these schemes, they might not be able to tell whether the scheme correctly performs the authorization in a way that cannot be bypassed or subverted by an attacker.

Automated Dynamic Analysis

Automated dynamic analysis may not be able to find interfaces that are protected by authorization checks, even if those checks contain weaknesses.

Manual Analysis

Moderate
This weakness can be detected using tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session. Specifically, manual static analysis is useful for evaluating the correctness of custom authorization mechanisms.

These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules. However, manual efforts might not achieve desired code coverage within limited time constraints.

Manual Static Analysis - Binary or Bytecode

SOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Dynamic Analysis with Automated Results Interpretation

SOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Web Application Scanner Web Services Scanner Database Scanners

Dynamic Analysis with Manual Results Interpretation

SOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Host Application Interface Scanner Fuzz Tester Framework-based Fuzzer Forced Path Execution Monitored Virtual Environment - run potentially malicious code in sandbox / wrapper / virtual machine, see if it does anything suspicious

Manual Static Analysis - Source Code

SOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Focused Manual Spotcheck - Focused manual analysis of source Manual Source Code Review (not inspections)

Automated Static Analysis - Source Code

SOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Context-configured Source Code Weakness Analyzer

Architecture or Design Review

High
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Formal Methods / Correct-By-Construction ``` Cost effective for partial coverage: ``` Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

MITRE diagram

Weakness relationships and flow

CWE-863 MITRE diagramı