Description
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 restrictions.
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.
Modes of Introduction:
– Architecture and Design
Likelihood of Exploit: High
Related Weaknesses
Consequences
Confidentiality: Read Application Data, Read 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 data.
Integrity: Modify Application Data, Modify 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 or Assume Identity, Bypass Protection Mechanism
An attacker could gain privileges by modifying or reading critical data directly, or by accessing privileged functionality.
Potential Mitigations
Phase: Architecture and Design
Effectiveness:
Description:
Phase: Architecture and Design
Effectiveness:
Description:
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].
Phase: Architecture and Design
Effectiveness:
Description:
Phase: Architecture and Design
Effectiveness:
Description:
Phase: System Configuration, Installation
Effectiveness:
Description:
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.
CVE References
- CVE-2019-15900
- Chain: sscanf() call is used to check if a username and group exists, but the return value of sscanf() call is not checked (CWE-252), causing an uninitialized variable to be checked (CWE-457), returning success to allow authorization bypass for executing a privileged (CWE-863).
- 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.