CWE-645 Base Incompleto High likelihood

Overly Restrictive Account Lockout Mechanism

This vulnerability occurs when an application's account lockout feature is too strict, allowing attackers to easily trigger it and lock legitimate users out of their accounts, causing a denial of…

Definição

What is CWE-645?

This vulnerability occurs when an application's account lockout feature is too strict, allowing attackers to easily trigger it and lock legitimate users out of their accounts, causing a denial of service.
Account lockout is a common defense against password-guessing attacks, temporarily disabling an account after several failed login attempts. However, if configured too aggressively—with a very low attempt threshold or an excessively long lockout period—this protective measure can be turned against the system itself. Attackers can exploit this by intentionally failing login attempts for targeted user accounts, denying access to legitimate users. To prevent this, developers must balance security with usability, ensuring lockout policies are strict enough to deter brute-force attacks but not so restrictive that they enable easy denial-of-service.
Impacto no mundo real

Real-world CVEs caused by CWE-645

Ainda não há referências CVE públicas associadas a este CWE no catálogo da MITRE.

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    Identificar um caminho de código que trata input não confiável sem validação.

  2. 2

    Criar um payload que explora o comportamento inseguro — injeção, traversal, overflow ou abuso de lógica.

  3. 3

    Entregar o payload através de um pedido normal e observar a reação da aplicação.

  4. 4

    Iterar até que a resposta exponha dados, execute código do atacante ou escale privilégios.

Exemplo de código vulnerável

Vulnerable pseudo

A MITRE não publicou um exemplo de código para este CWE. O padrão abaixo é ilustrativo — consulte os Recursos para referências canónicas.

Vulnerável pseudo
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
Exemplo de código seguro

Secure pseudo

Seguro 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-645

  • Architecture and Design Implement more intelligent password throttling mechanisms such as those which take IP address into account, in addition to the login name.
  • Architecture and Design Implement a lockout timeout that grows as the number of incorrect login attempts goes up, eventually resulting in a complete lockout.
  • Architecture and Design Consider alternatives to account lockout that would still be effective against password brute force attacks, such as presenting the user machine with a puzzle to solve (makes it do some computation).
Sinais de deteção

How to detect CWE-645

SAST High

Executar análise estática (SAST) na base de código à procura do padrão inseguro no fluxo de dados.

DAST Moderate

Executar testes dinâmicos de segurança de aplicações (DAST) contra o endpoint em execução.

Runtime Moderate

Monitorizar os registos em tempo de execução para traços de exceção invulgares, input malformado ou tentativas de contornar a autorização.

Code review Moderate

Revisão de código: sinalizar qualquer novo código que trate input desta superfície sem usar os ajudantes validados do framework.

CWE-645

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

Frequently asked questions

O que é o CWE-645?

This vulnerability occurs when an application's account lockout feature is too strict, allowing attackers to easily trigger it and lock legitimate users out of their accounts, causing a denial of service.

Qual a gravidade do CWE-645?

A MITRE classifica a probabilidade de exploração como Alta — esta fraqueza é ativamente explorada em campo e deve ser priorizada para remediação.

Que linguagens ou plataformas são afetadas pelo CWE-645?

A MITRE não especificou as plataformas afetadas por este CWE — pode aplicar-se à maioria das stacks de aplicações.

Como posso prevenir o CWE-645?

Implement more intelligent password throttling mechanisms such as those which take IP address into account, in addition to the login name. Implement a lockout timeout that grows as the number of incorrect login attempts goes up, eventually resulting in a complete lockout.

Como é que o Plexicus deteta e corrige o CWE-645?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-645 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-645?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/645.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-645

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Improper Certificate Validation

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CWE-306 Irmão

Missing Authentication for Critical Function

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Improper Restriction of Excessive Authentication Attempts

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SAMPLE HANDOVER · ILLUSTRATIVE

Sample evidence handover

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VALIDATED FINDING Evidence attached

Server-Side Request Forgery in webhooks/receiver

demo-project/sample-app · src/webhooks/receiver.py:42

SeverityHigh CVSS 3.18.6 Priority79 Confirmedvia replay

Untrusted caller-supplied URLs reach an internal egress without an allowlist. Replayed in a sandbox against a fresh authorized target — the same control was validated to fail twice.

REVIEWER-READY REMEDIATION Merge-ready PR

Validate the target URL against an allowlist of permitted hostnames. Reject private/internal IP ranges. Enforce HTTPS only.

plexicus/remediation/webhooks-ssrf 3 changed · 0 new files
42resp = requests.get(target_url)
42+if not is_allowed_host(target_url):
43+  raise WebhookRejected(target_url)
44+resp = requests.get(target_url, timeout=5)
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  • Validated findings list
  • Merge-ready PRs
  • Compliance mapping (NIS2 · DORA · CRA)
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