Interpretation Conflict

Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.


This is generally found in proxies, firewalls, anti-virus software, and other intermediary devices that monitor, allow, deny, or modify traffic based on how the client or server is expected to behave.


The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

The paper "Insertion, Evasion, and Denial of Service: Eluding Network Intrusion Detection" [REF-428] shows that OSes varied widely in how they manage unusual packets, which made it difficult or impossible for intrusion detection systems to properly detect certain attacker manipulations that took advantage of these OS differences.

Example Two

Null characters have different interpretations in Perl and C, which have security consequences when Perl invokes C functions. Similar problems have been reported in ASP [REF-429] and PHP.

See Also

Comprehensive Categorization: Component Interaction

Weaknesses in this category are related to component interaction.

SFP Secondary Cluster: Protocol Error

This category identifies Software Fault Patterns (SFPs) within the Protocol Error cluster.

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Weaknesses for Simplified Mapping of Published Vulnerabilities

CWE entries in this view (graph) may be used to categorize potential weaknesses within sources that handle public, third-party vulnerability information, such as the N...

Weaknesses Introduced During Implementation

This view (slice) lists weaknesses that can be introduced during implementation.

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