CWE-331 Detalhe

CWE-331

Insufficient Entropy
Draft
2006-07-19
00h00 +00:00
2025-12-11
00h00 +00:00
CWE Mitre.org
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Nome: Insufficient Entropy

The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others.

Informações Gerais

Modos de Introdução

Architecture and Design
Implementation : REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Plataformas Aplicáveis

Linguagem

Class: Not Language-Specific (Undetermined)

Consequências Comuns

Escopo Impacto Probabilidade
Access Control
Other		Bypass Protection Mechanism, Other

Note: An attacker could guess the random numbers generated and could gain unauthorized access to a system if the random numbers are used for authentication and authorization.

Exemplos Observados

Referências Descrição

CVE-2001-0950

Insufficiently random data used to generate session tokens using C rand(). Also, for certificate/key generation, uses a source that does not block when entropy is low.

CVE-2008-2108

Chain: insufficient precision (CWE-1339) in random-number generator causes some zero bits to be reliably generated, reducing the amount of entropy (CWE-331)

Mitigações Potenciais

Phases : Implementation
Determine the necessary entropy to adequately provide for randomness and predictability. This can be achieved by increasing the number of bits of objects such as keys and seeds.

Métodos de Detecção

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.)

Notas de Mapeamento de Vulnerabilidade

Justificativa : 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.
Comentário : 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.

Padrões de Ataque Relacionados

CAPEC-ID Nome do Padrão de Ataque
CAPEC-59 Session Credential Falsification through Prediction
This attack targets predictable session ID in order to gain privileges. The attacker can predict the session ID used during a transaction to perform spoofing and session hijacking.

Notas

As of CWE 4.5, terminology related to randomness, entropy, and predictability can vary widely. Within the developer and other communities, "randomness" is used heavily. However, within cryptography, "entropy" is distinct, typically implied as a measurement. There are no commonly-used definitions, even within standards documents and cryptography papers. Future versions of CWE will attempt to define these terms and, if necessary, distinguish between them in ways that are appropriate for different communities but do not reduce the usability of CWE for mapping, understanding, or other scenarios.

Referências

REF-207

Building Secure Software: How to Avoid Security Problems the Right Way
John Viega, Gary McGraw.

Submissão

Nome Organização Data Data de lançamento Version
PLOVER 2006-07-19 +00:00 2006-07-19 +00:00 Draft 3

Modificações

Nome Organização Data Comentário
Eric Dalci Cigital 2008-07-01 +00:00 updated Time_of_Introduction
CWE Content Team MITRE 2008-09-08 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2010-02-16 +00:00 updated Taxonomy_Mappings
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences
CWE Content Team MITRE 2012-05-11 +00:00 updated Common_Consequences, Demonstrative_Examples, References, Relationships
CWE Content Team MITRE 2012-10-30 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2015-12-07 +00:00 updated Relationships
CWE Content Team MITRE 2017-11-08 +00:00 updated Applicable_Platforms, Modes_of_Introduction, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2019-01-03 +00:00 updated Relationships
CWE Content Team MITRE 2019-06-20 +00:00 updated Relationships
CWE Content Team MITRE 2020-02-24 +00:00 updated Relationships
CWE Content Team MITRE 2021-07-20 +00:00 updated Maintenance_Notes, Observed_Examples
CWE Content Team MITRE 2021-10-28 +00:00 updated Relationships
CWE Content Team MITRE 2023-01-31 +00:00 updated Description
CWE Content Team MITRE 2023-04-27 +00:00 updated Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2025-12-11 +00:00 updated Detection_Factors, Relationships, Weakness_Ordinalities
As informações apresentadas no CVE Find originam-se de várias fontes de referência cuidadosamente selecionadas. Os dados CVE são fornecidos pela MITRE Corporation e pelo National Vulnerability Database (NVD). O catálogo de Vulnerabilidades Conhecidas Exploradas (KEV) é proveniente da Cybersecurity and Infrastructure Security Agency (CISA), enquanto as pontuações EPSS vêm do FIRST.org. Além disso, os dados sobre fraquezas de software (CWE) e padrões de ataque comuns (CAPEC) são mantidos pela MITRE Corporation, e as informações sobre configurações de hardware e software (CPE) são fornecidas pelo NVD.