CWE-342 Detalhe

CWE-342

Predictable Exact Value from Previous Values
Draft
2006-07-19
00h00 +00:00
2025-12-11
00h00 +00:00
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Nome: Predictable Exact Value from Previous Values

An exact value or random number can be precisely predicted by observing previous values.

Informações Gerais

Modos de Introdução

Architecture and Design
Implementation

Plataformas Aplicáveis

Linguagem

Class: Not Language-Specific (Undetermined)

Consequências Comuns

Escopo Impacto Probabilidade
OtherVaries by Context

Exemplos Observados

Referências Descrição

CVE-2002-1463

Firewall generates easily predictable initial sequence numbers (ISN), which allows remote attackers to spoof connections.

CVE-1999-0074

Listening TCP ports are sequentially allocated, allowing spoofing attacks.

CVE-1999-0077

Predictable TCP sequence numbers allow spoofing.

CVE-2000-0335

DNS resolver uses predictable IDs, allowing a local user to spoof DNS query results.

Mitigações Potenciais

Increase the entropy used to seed a PRNG.
Phases : Architecture and Design // Requirements
Use products or modules that conform to FIPS 140-2 [REF-267] to avoid obvious entropy problems. Consult FIPS 140-2 Annex C ("Approved Random Number Generators").
Phases : Implementation
Use a PRNG that periodically re-seeds itself using input from high-quality sources, such as hardware devices with high entropy. However, do not re-seed too frequently, or else the entropy source might block.

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.

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-267

FIPS PUB 140-2: SECURITY REQUIREMENTS FOR CRYPTOGRAPHIC MODULES
Information Technology Laboratory, National Institute of Standards and Technology.
https://csrc.nist.gov/files/pubs/fips/140-2/upd2/final/docs/fips1402.pdf

REF-44

24 Deadly Sins of Software Security
Michael Howard, David LeBlanc, John Viega.

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 2009-03-10 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2009-12-28 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2010-06-21 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences
CWE Content Team MITRE 2011-06-27 +00:00 updated Common_Consequences
CWE Content Team MITRE 2011-09-13 +00:00 updated Potential_Mitigations, References
CWE Content Team MITRE 2012-05-11 +00:00 updated Observed_Examples, References, Relationships
CWE Content Team MITRE 2012-10-30 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2017-11-08 +00:00 updated Applicable_Platforms, References
CWE Content Team MITRE 2020-02-24 +00:00 updated Relationships
CWE Content Team MITRE 2021-07-20 +00:00 updated Maintenance_Notes
CWE Content Team MITRE 2023-04-27 +00:00 updated References, Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2025-09-09 +00:00 updated References
CWE Content Team MITRE 2025-12-11 +00:00 updated Relationships, Weakness_Ordinalities