CWE-179: Incorrect Behavior Order: Early Validation
Incorrect Behavior Order: Early Validation
Weakness ID: 179 (Weakness Base)
Status: Incomplete
Description
Description Summary
The software validates input before applying protection mechanisms that modify the input, which could allow an attacker to bypass the validation via dangerous inputs that only arise after the modification.
Extended Description
Software needs to validate data at the proper time, after data has been canonicalized and cleansed. Early validation is susceptible to various manipulations that result in dangerous inputs that are produced by canonicalization and cleansing.
Time of Introduction
Implementation
Applicable Platforms
Languages
All
Modes of Introduction
Since early validation errors usually arise from improperly implemented
defensive mechanisms, it is likely that these will be introduced more
frequently as secure programming becomes implemented more widely.
Common Consequences
Scope
Effect
Access Control
Technical Impact: Bypass protection
mechanism
Potential Mitigations
Phase: Implementation
Strategy: Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass whitelist validation schemes by introducing dangerous inputs after they have been checked.
Description
