Use of Hard-coded, Security-relevant Constants

Draft Base

Structure: Simple

Description

The product uses hard-coded constants instead of symbolic names for security-critical values, which increases the likelihood of mistakes during code maintenance or security policy change.

Extended Description

If the developer does not find all occurrences of the hard-coded constants, an incorrect policy decision may be made if one of the constants is not changed. Making changes to these values will require code changes that may be difficult or impossible once the system is released to the field. In addition, these hard-coded values may become available to attackers if the code is ever disclosed.

Common Consequences 1

Scope: Other

Impact: Varies by ContextQuality Degradation

The existence of hardcoded constants could cause unexpected behavior and the introduction of weaknesses during code maintenance or when making changes to the code if all occurrences are not modified. The use of hardcoded constants is an indication of poor quality.

Detection Methods 1

Automated Static AnalysisHigh

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Potential Mitigations 1

Phase: Implementation

Avoid using hard-coded constants. Configuration files offer a more flexible solution.

Demonstrative Examples 1

ID : DX-215

The usage of symbolic names instead of hard-coded constants is preferred.

The following is an example of using a hard-coded constant instead of a symbolic name.

Code Example:Bad
C
c

If the buffer value needs to be changed, then it has to be altered in more than one place. If the developer forgets or does not find all occurrences, in this example it could lead to a buffer overflow.

Code Example:Good
C
c

In this example the developer will only need to change one value and all references to the buffer size are updated, as a symbolic name is used instead of a hard-coded constant.

Modes of Introduction

Implementation

Related Weaknesses

ChildOf:

Inappropriate Source Code Style or Formatting (CWE-1078)

Taxonomy Mapping

CERT C Secure Coding