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CWE-341 Base Rascunho
Predictable from Observable State
This vulnerability occurs when an attacker can guess or deduce sensitive values, like random numbers or identifiers, by observing predictable system or network characteristics such as timestamps,…
Definição
What is CWE-341?
This vulnerability occurs when an attacker can guess or deduce sensitive values, like random numbers or identifiers, by observing predictable system or network characteristics such as timestamps, process IDs, or other public information.
This weakness undermines security by making supposedly random or secret values guessable. Instead of being truly unpredictable, these values follow a pattern or are derived from observable system state, like the current time, incrementing counters, or publicly accessible identifiers. Attackers can exploit this to predict session tokens, cryptographic nonces, or temporary file names, leading to unauthorized access or data breaches.
To prevent this, developers must ensure that all security-critical values are generated using cryptographically secure random number generators (CSPRNGs) designed to resist prediction. Avoid using predictable sources like system time, process IDs, or unseeded pseudo-random functions for secrets, tokens, or initialization vectors. Always validate that randomness sources are appropriate for the security context of the feature you are building.
Impacto no mundo real
Real-world CVEs caused by CWE-341
-
Mail server stores private mail messages with predictable filenames in a world-executable directory, which allows local users to read private mailing list archives.
-
PRNG allows attackers to use the output of small PRNG requests to determine the internal state information, which could be used by attackers to predict future pseudo-random numbers.
-
DNS resolver library uses predictable IDs, which allows a local attacker to spoof DNS query results.
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MFV. predictable filename and insecure permissions allows file modification to execute SQL queries.
Como os atacantes a exploram
Trajeto do atacante passo a passo
- 1
This code generates a unique random identifier for a user's session.
- 2
Because the seed for the PRNG is always the user's ID, the session ID will always be the same. An attacker could thus predict any user's session ID and potentially hijack the session.
- 3
This example also exhibits a Small Seed Space (CWE-339).
Exemplo de código vulnerável
Vulnerable PHP
This code generates a unique random identifier for a user's session.
function generateSessionID($userID){
srand($userID);
return rand();
} Exemplo de código seguro
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Lista de verificação de prevenção
How to prevent CWE-341
- Implementation Increase the entropy used to seed a PRNG.
- 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").
- 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.
Sinais de deteção
How to detect CWE-341
Executar testes dinâmicos de segurança de aplicações (DAST) contra o endpoint em execução.
Monitorizar os registos em tempo de execução para traços de exceção invulgares, input malformado ou tentativas de contornar a autorização.
Revisão de código: sinalizar qualquer novo código que trate input desta superfície sem usar os ajudantes validados do framework.
CWE-341
Don't catalog this weakness. Prove it's reachable.
Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.
Perguntas frequentes O que é o CWE-341?
Qual a gravidade do CWE-341?
Que linguagens ou plataformas são afetadas pelo CWE-341?
Como posso prevenir o CWE-341?
Como é que o Plexicus deteta e corrige o CWE-341?
Onde posso saber mais sobre o CWE-341?
Frequently asked questions
O que é o CWE-341?
This vulnerability occurs when an attacker can guess or deduce sensitive values, like random numbers or identifiers, by observing predictable system or network characteristics such as timestamps, process IDs, or other public information.
Qual a gravidade do CWE-341?
A MITRE não publicou uma classificação de probabilidade de exploração para esta fraqueza. Trate-a como impacto médio até o seu modelo de ameaças provar o contrário.
Que linguagens ou plataformas são afetadas pelo CWE-341?
A MITRE não especificou as plataformas afetadas por este CWE — pode aplicar-se à maioria das stacks de aplicações.
Como posso prevenir o CWE-341?
Increase the entropy used to seed a PRNG. 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").
Como é que o Plexicus deteta e corrige o CWE-341?
O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-341 em cada commit. Quando é encontrada uma correspondência, o nosso agente Codex Remedium abre um PR de correção com o código corrigido, testes e um resumo de uma linha para o revisor.
Onde posso saber mais sobre o CWE-341?
A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/341.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.
Fraquezas relacionadas
Weaknesses related to CWE-341
CWE-340 Pai
Generation of Predictable Numbers or Identifiers
This vulnerability occurs when a system creates numbers or identifiers that are too easy to guess, undermining security mechanisms that…
CWE-342 Irmão
Predictable Exact Value from Previous Values
This vulnerability occurs when a system uses a predictable sequence for generating values, allowing an attacker to accurately guess future…
CWE-343 Irmão
Predictable Value Range from Previous Values
This vulnerability occurs when a system's random number generator produces values that, after observing previous outputs, allow an…
Pronto para validar o que importa?
Pronto para validar o que importa.
O Plexicus é Proof-Driven AppSec: achados validados, compreensão contextual e remediação revisada — ancorada em evidência, escopada com você.