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CWE-640 Base Incompleto
Weak Password Recovery Mechanism for Forgotten Password
This vulnerability occurs when an application's password reset or recovery feature is poorly designed or implemented, allowing attackers to bypass authentication and hijack user accounts.
Definição
What is CWE-640?
This vulnerability occurs when an application's password reset or recovery feature is poorly designed or implemented, allowing attackers to bypass authentication and hijack user accounts.
Password recovery is a necessary feature, but it often becomes the weakest link in your authentication system. Common flaws include using easily guessed security questions (answers found on social media), sending the original password instead of a secure temporary one, or failing to limit reset attempts, which enables denial-of-service attacks. Attackers exploit these oversights to impersonate legitimate users, completely undermining even strong initial password policies.
To prevent this, treat the recovery mechanism with the same security rigor as the primary login. Always generate a time-limited, single-use token sent to a pre-verified contact method. Implement robust rate-limiting and audit logs for all recovery attempts. The goal is to verify the user's identity securely without creating a new, exploitable path into the account.
Impacto no mundo real
Real-world CVEs caused by CWE-640
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
Identificar um caminho de código que trata input não confiável sem validação.
- 2
Criar um payload que explora o comportamento inseguro — injeção, traversal, overflow ou abuso de lógica.
- 3
Entregar o payload através de um pedido normal e observar a reação da aplicação.
- 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.
// 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
// 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-640
- Architecture and Design Make sure that all input supplied by the user to the password recovery mechanism is thoroughly filtered and validated.
- Architecture and Design Do not use standard weak security questions and use several security questions.
- Architecture and Design Make sure that there is throttling on the number of incorrect answers to a security question. Disable the password recovery functionality after a certain (small) number of incorrect guesses.
- Architecture and Design Require that the user properly answers the security question prior to resetting their password and sending the new password to the e-mail address of record.
- Architecture and Design Never allow the user to control what e-mail address the new password will be sent to in the password recovery mechanism.
- Architecture and Design Assign a new temporary password rather than revealing the original password.
Sinais de deteção
How to detect CWE-640
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-640
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-640?
Qual a gravidade do CWE-640?
Que linguagens ou plataformas são afetadas pelo CWE-640?
Como posso prevenir o CWE-640?
Como é que o Plexicus deteta e corrige o CWE-640?
Onde posso saber mais sobre o CWE-640?
Frequently asked questions
O que é o CWE-640?
This vulnerability occurs when an application's password reset or recovery feature is poorly designed or implemented, allowing attackers to bypass authentication and hijack user accounts.
Qual a gravidade do CWE-640?
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-640?
A MITRE não especificou as plataformas afetadas por este CWE — pode aplicar-se à maioria das stacks de aplicações.
Como posso prevenir o CWE-640?
Make sure that all input supplied by the user to the password recovery mechanism is thoroughly filtered and validated. Do not use standard weak security questions and use several security questions.
Como é que o Plexicus deteta e corrige o CWE-640?
O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-640 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-640?
A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/640.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.
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Pronto para validar o que importa.
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