Permissive Whitelist| ID: 183 | Date: (C)2012-05-14 (M)2022-10-10 |
| Type: weakness | Status: DRAFT |
| Abstraction Type: Base |
Description
An application uses a "whitelist" of acceptable values, but the
whitelist includes at least one unsafe value, leading to resultant
weaknesses.
Applicable PlatformsLanguage Class: All
Time Of Introduction
Related Attack Patterns
Common Consequences
| Scope | Technical Impact | Notes |
|---|
| Access_Control | Bypass protection
mechanism | |
Detection MethodsNone
Potential Mitigations
| Phase | Strategy | Description | Effectiveness | Notes |
|---|
| | | Define rigid requirements specifications for input and strictly accept
input based on those specifications. Determine if any of the valid data
include special characters that are associated with security exploits
(use this taxonomy and the Common Vulnerabilities and Exposures as a
start to determine what characters are potentially malicious). If
permitted, then follow the potential mitigations associated with the
weaknesses in this taxonomy. Always handle these data carefully and
anticipate attempts to exploit your system. | | |
| Implementation | Input Validation | Assume all input is malicious. Use an "accept known good" input
validation strategy, i.e., use a whitelist of acceptable inputs that
strictly conform to specifications. Reject any input that does not
strictly conform to specifications, or transform it into something that
does.When performing input validation, consider all potentially relevant
properties, including length, type of input, the full range of
acceptable values, missing or extra inputs, syntax, consistency across
related fields, and conformance to business rules. As an example of
business rule logic, "boat" may be syntactically valid because it only
contains alphanumeric characters, but it is not valid if the input is
only expected to contain colors such as "red" or "blue."Do not rely exclusively on looking for malicious or malformed inputs
(i.e., do not rely on a blacklist). A blacklist is likely to miss at
least one undesirable input, especially if the code's environment
changes. This can give attackers enough room to bypass the intended
validation. However, blacklists can be useful for detecting potential
attacks or determining which inputs are so malformed that they should be
rejected outright. | | |
Relationships
| Related CWE | Type | View | Chain |
|---|
| CWE-183 ChildOf CWE-896 | Category | CWE-888 | |
Demonstrative ExamplesNone
White Box Definitions None
Black Box Definitions None
Taxynomy Mappings
| Taxynomy | Id | Name | Fit |
|---|
| PLOVER | | Permissive Whitelist | |
References:
- Mark Dowd John McDonald Justin Schuh .The Art of Software Security Assessment 1st Edition. Addison Wesley. Section:'Chapter 8, "Eliminating Metacharacters", Page
435.'. Published on 2006.
