CWE-758: Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
The product uses an API function, data structure, or other entity in a way that relies on properties that are not always guaranteed to hold for that entity.
How it's found
Reliance on Undefined, Unspecified, or Implementation-Defined Behavior describes a general pattern rather than a single fixed bug. Testers use a mix of static analysis and manual code review to find where a target's code matches this pattern, then confirm exploitability by hand.
This can lead to resultant weaknesses when the required properties change, such as when the product is ported to a different platform or if an interaction error (CWE-435) occurs.
Consequences
- Reduce Maintainability, Unexpected State, Quality Degradation
Where this fits in a TurboPentest engagement
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Frequently asked questions
What is CWE-758?
The product uses an API function, data structure, or other entity in a way that relies on properties that are not always guaranteed to hold for that entity.
How do you find Reliance on Undefined, Unspecified, or Implementation-Defined Behavior?
Reliance on Undefined, Unspecified, or Implementation-Defined Behavior describes a general pattern rather than a single fixed bug. Testers use a mix of static analysis and manual code review to find where a target's code matches this pattern, then confirm exploitability by hand.
What is the impact of CWE-758?
Reduce Maintainability, Unexpected State, Quality Degradation
Does TurboPentest test for Reliance on Undefined, Unspecified, or Implementation-Defined Behavior?
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Related CWEs
Written and reviewed by
Michel Chamberland - Founder & CEO, IntegSec
CISSP, OSCP, OSCE, CEH, GIAC, CCSK · 20+ years in offensive security
Michel has spent 20+ years on offensive security teams including IBM X-Force Red and Trustwave SpiderLabs, leading penetration tests, red team engagements, and breach response for Fortune 500 customers. He is the founder of IntegSec and the architect of TurboPentest.
Find these issues before an attacker does
TurboPentest runs an agentic AI pentest against your target and reports findings with proof, from $99 per target.
Start a pentest