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Status: Incomplete Weakness ID: 128 (Weakness Base)Description Summary 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. Likelihood of Exploit Medium Weakness Ordinalities Primary (where the weakness exists independent of other weaknesses) Causal Nature Explicit (an explicit
weakness resulting from behavior of the developer) Common Consequences Availability Wrap-around errors generally lead to undefined behavior, infinite loops, and therefore crashes. Integrity 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. Access control (instruction processing): A wrap around 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 Requirements specification: The choice could be made to use a language that is not susceptible to these issues. Architecture and Design Provide clear upper and lower bounds on the scale of any protocols designed. Implementation Place sanity checks on all incremented variables to ensure that they remain within reasonable bounds. Background Details 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 fail to 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. Relationships
Relationship Notes The relationship between overflow and wrap-around needs to be examined more closely, since several entries (including CWE-190) are closely related. Taxonomy Mappings
Applicable Platforms Languages C (Often) C++ (Often) Time of Introduction  ImplementationRelated Attack Patterns
Content History Submissions CLASP. (Externally Mined) Modifications CWE Content Team. MITRE. 2008-09-08. (Internal) updated Applicable_Platforms, Background_Details, Common_Consequences, Relationships, Relationship_Notes, Taxonomy_Mappings, Weakness_Ordinalities |
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