CAPEC-71 : Using Unicode Encoding to Bypass Validation Logic
An attacker may provide a Unicode string to a system component that is not Unicode aware and use that to circumvent the filter or cause the classifying mechanism to fail to properly understanding the request. That may allow the attacker to slip malicious data past the content filter and/or possibly cause the application to route the request incorrectly.
https://capec.mitre.org/data/definitions/71.htmlRelated CWE definitions
The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
The product does not properly encode or decode the data, resulting in unexpected values.
The product does not properly handle when an input uses an alternate encoding that is valid for the control sphere to which the input is being sent.
The product does not properly handle when an input contains Unicode encoding.
The product 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.
The product validates input before it is canonicalized, which prevents the product from detecting data that becomes invalid after the canonicalization step.
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are explicitly allowed by policy because the inputs are assumed to be safe, but the list is too permissive - that is, it allows an input that is unsafe, leading to resultant weaknesses.
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.
The product uses a denylist-based protection mechanism to defend against XSS attacks, but the denylist is incomplete, allowing XSS variants to succeed.
The product compares two entities in a security-relevant context, but the comparison is incorrect, which may lead to resultant weaknesses.
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