|ID: 863||Date: (C)2012-05-14 (M)2012-11-08|
|Type: weakness||Status: INCOMPLETE|
|Abstraction Type: Class|
The software performs an authorization check when an actor
attempts to access a resource or perform an action, but it does not correctly
perform the check. This allows attackers to bypass intended access
Extended DescriptionAssuming a user with a given identity, authorization is the process of
determining whether that user can access a given resource, based on the
user's privileges and any permissions or other access-control specifications
that apply to the resource.When access control checks is incorrectly applied, users are able to
access data or perform actions that they should not be allowed to perform.
This can lead to a wide range of problems, including information exposures,
denial of service, and arbitrary code execution.
Likelihood of Exploit: High
Applicable PlatformsLanguage Class: Language-independentTechnology Class: Web-ServerTechnology Class: OftenTechnology Class: Database-ServerTechnology Class: Often
Time Of Introduction
- Architecture and Design
Related Attack Patterns
|Confidentiality ||Read application
dataRead files or
directories ||An attacker could 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
|Integrity ||Modify application
dataModify files or
directories ||An attacker could 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. |
|Access_Control ||Gain privileges / assume
mechanism ||An attacker could gain privileges by modifying or reading critical
data directly, or by accessing privileged functionality. |
|Automated Static Analysis ||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. ||Limited || |
|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 ||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. ||Moderate || |
|Architecture and Design || ||Divide the software 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)
[R.863.1] 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 || ||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 [R.863.2]. || || |
|Architecture and Design ||Libraries or Frameworks ||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 [R.863.4] and the OWASP ESAPI Access Control
feature [R.863.5]. || || |
|Architecture and Design || ||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 ConfigurationInstallation || ||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. || || |
|CWE-863 ChildOf CWE-817 ||Category ||CWE-809 || |
Demonstrative Examples (Details)
- The following code could be for a medical records application. It
displays a record to already authenticated users, confirming the user's
authorization using a value stored in a cookie.
- CVE-2009-2213 : Gateway uses default "Allow" configuration for its authorization settings.
- CVE-2009-0034 : Chain: product does not properly interpret a configuration option for a system group, allowing users to gain privileges.
- CVE-2008-6123 : Chain: SNMP product does not properly parse a configuration option for which hosts are allowed to connect, allowing unauthorized IP addresses to connect.
- CVE-2008-7109 : Chain: reliance on client-side security (CWE-602) allows attackers to bypass authorization using a custom client.
- CVE-2008-3424 : Chain: product does not properly handle wildcards in an authorization policy list, allowing unintended access.
- CVE-2008-4577 : ACL-based protection mechanism treats negative access rights as if they are positive, allowing bypass of intended restrictions.
- CVE-2006-6679 : Product relies on the X-Forwarded-For HTTP header for authorization, allowing unintended access by spoofing the header.
- CVE-2005-2801 : Chain: file-system code performs an incorrect comparison (CWE-697), preventing default ACLs from being properly applied.
- CVE-2001-1155 : Chain: product does not properly check the result of a reverse DNS lookup because of operator precedence (CWE-783), allowing bypass of DNS-based access restrictions.
For more examples, refer to CVE relations in the bottom box.
White Box Definitions None
Black Box Definitions None
- NIST .Role Based Access Control and Role Based
- M. Howard D. LeBlanc .Writing Secure Code 2nd Edition. Microsoft. Section:'Chapter 4, "Authorization" Page 114; Chapter 6, "Determining
Appropriate Access Control" Page 171'. Published on 2002.
- Frank Kim .Top 25 Series - Rank 5 - Improper Access Control
(Authorization). SANS Software Security Institute. 2010-03-04.
- Rahul Bhattacharjee .Authentication using JAAS.
- OWASP .OWASP Enterprise Security API (ESAPI) Project.
- Mark Dowd John McDonald Justin Schuh .The Art of Software Security Assessment 1st Edition. Addison Wesley. Section:'Chapter 2, "Common Vulnerabilities of Authorization", Page
39.'. Published on 2006.