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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
