Détail du CWE-33

The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize '....' (multiple dot) sequences that can resolve to a location that is outside of that directory.

Modes d'introduction

Implementation

Plateformes applicables

Langue

Class: Not Language-Specific (Undetermined)

Technologies

Class: Not Technology-Specific (Undetermined)
Class: Web Based (Undetermined)

Conséquences courantes

Exemples observés

Mesures d’atténuation potentielles

Phases : Implementation
Phases : Implementation
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 allowlist validation schemes by introducing dangerous inputs after they have been checked.

Méthodes de détection

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Notes de cartographie des vulnérabilités

Justification : This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Commentaire : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Notes

Like the triple-dot CWE-32, this manipulation probably hides multiple weaknesses that should be made more explicit.

Soumission

Modifications