Description

Wrap around errors occur whenever a value is incremented past the maximum value for its type and therefore “wraps around” to a very small, negative, or undefined value.

Due to how addition is performed by computers, if a primitive is incremented past the maximum value possible for its storage space, the system will not recognize this, and therefore increment each bit as if it still had extra space. Because of how negative numbers are represented in binary, primitives interpreted as signed may “wrap” to very large negative values.

Modes of Introduction:

– Implementation

Likelihood of Exploit: Medium

Related Weaknesses

CWE-682
CWE-119
CWE-190

Consequences

Availability: DoS: Crash, Exit, or Restart, DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory), DoS: Instability

This weakness will generally lead to undefined behavior and therefore crashes. In the case of overflows involving loop index variables, the likelihood of infinite loops is also high.

Integrity: Modify Memory

If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the wrap around results in other conditions such as buffer overflows, further memory corruption may occur.

Confidentiality, Availability, Access Control: Execute Unauthorized Code or Commands, Bypass Protection Mechanism

This weakness can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program’s implicit security policy.

Potential Mitigations

Phase:

Description: 

Requirements specification: The choice could be made to use a language that is not susceptible to these issues.

Phase: Architecture and Design

Description: 

Provide clear upper and lower bounds on the scale of any protocols designed.

Phase: Implementation

Description: 

Perform validation on all incremented variables to ensure that they remain within reasonable bounds.

CVE References