Détail du CWE-186

CWE-186

Overly Restrictive Regular Expression
Draft
2006-07-19
00h00 +00:00
2023-06-29
00h00 +00:00
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Nom: Overly Restrictive Regular Expression

A regular expression is overly restrictive, which prevents dangerous values from being detected.

Description du CWE

This weakness is not about regular expression complexity. Rather, it is about a regular expression that does not match all values that are intended. Consider the use of a regexp to identify acceptable values or to spot unwanted terms. An overly restrictive regexp misses some potentially security-relevant values leading to either false positives *or* false negatives, depending on how the regexp is being used within the code. Consider the expression /[0-8]/ where the intention was /[0-9]/. This expression is not "complex" but the value "9" is not matched when maybe the programmer planned to check for it.

Informations générales

Modes d'introduction

Implementation

Plateformes applicables

Langue

Class: Not Language-Specific (Undetermined)

Conséquences courantes

Portée Impact Probabilité
Access ControlBypass Protection Mechanism

Exemples observés

Références Description

CVE-2005-1604

MIE. ".php.ns" bypasses ".php$" regexp but is still parsed as PHP by Apache. (manipulates an equivalence property under Apache)

Mesures d’atténuation potentielles

Phases : Implementation
Regular expressions can become error prone when defining a complex language even for those experienced in writing grammars. Determine if several smaller regular expressions simplify one large regular expression. Also, subject your regular expression to thorough testing techniques such as equivalence partitioning, boundary value analysis, and robustness. After testing and a reasonable confidence level is achieved, a regular expression may not be foolproof. If an exploit is allowed to slip through, then record the exploit and refactor your regular expression.

Notes de cartographie des vulnérabilités

Justification : This CWE entry is at the Base 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.

NotesNotes

Can overlap allowlist/denylist errors (CWE-183/CWE-184)

Soumission

Nom Organisation Date Date de publication Version
PLOVER 2006-07-19 +00:00 2006-07-19 +00:00 Draft 3

Modifications

Nom Organisation Date Commentaire
Eric Dalci Cigital 2008-07-01 +00:00 updated Potential_Mitigations, Time_of_Introduction
CWE Content Team MITRE 2008-09-08 +00:00 updated Relationships, Relationship_Notes, Taxonomy_Mappings
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences
CWE Content Team MITRE 2012-05-11 +00:00 updated Relationships
CWE Content Team MITRE 2014-07-30 +00:00 updated Relationships
CWE Content Team MITRE 2017-11-08 +00:00 updated Applicable_Platforms
CWE Content Team MITRE 2019-01-03 +00:00 updated Description
CWE Content Team MITRE 2020-02-24 +00:00 updated Description, Relationships
CWE Content Team MITRE 2020-06-25 +00:00 updated Relationship_Notes
CWE Content Team MITRE 2023-04-27 +00:00 updated Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes