CWE-296 Base Rascunho Low likelihood

Improper Following of a Certificate's Chain of Trust

This vulnerability occurs when software fails to properly validate the entire certificate chain back to a trusted root authority. This mistake can cause the system to incorrectly trust a certificate…

Definição

What is CWE-296?

This vulnerability occurs when software fails to properly validate the entire certificate chain back to a trusted root authority. This mistake can cause the system to incorrectly trust a certificate and the resource it represents, creating a security gap.
A certificate's trustworthiness isn't inherent; it's derived from a verifiable chain linking it back to a root certificate you already trust. If your code only checks the first link—or skips any intermediate certificates—you haven't actually verified the chain. This is like trusting an ID card because it looks official, without checking if the issuing authority is legitimate and properly authorized the person who issued it. The chain can break in several common ways. These include accepting a self-signed certificate (unless it's the designated root), failing to validate every intermediate certificate's constraints and signatures, or relying on a root certificate that has been compromised. Each skipped check creates an opportunity for an attacker to present a fraudulent certificate that your software will incorrectly accept as valid.
Impacto no mundo real

Real-world CVEs caused by CWE-296

  • CVE-2016-2402

    Server allows bypass of certificate pinning by sending a chain of trust that includes a trusted CA that is not pinned.

  • CVE-2008-4989

    Verification function trusts certificate chains in which the last certificate is self-signed.

  • CVE-2012-5821

    Chain: Web browser uses a TLS-related function incorrectly, preventing it from verifying that a server's certificate is signed by a trusted certification authority (CA).

  • CVE-2009-3046

    Web browser does not check if any intermediate certificates are revoked.

  • CVE-2009-0265

    chain: DNS server does not correctly check return value from the OpenSSL EVP_VerifyFinal function allows bypass of validation of the certificate chain.

  • CVE-2009-0124

    chain: incorrect check of return value from the OpenSSL EVP_VerifyFinal function allows bypass of validation of the certificate chain.

  • CVE-2002-0970

    File-transfer software does not validate Basic Constraints of an intermediate CA-signed certificate.

  • CVE-2002-0862

    Cryptographic API, as used in web browsers, mail clients, and other software, does not properly validate Basic Constraints.

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 C

This code checks the certificate of a connected peer.

Vulnerável C 
if ((cert = SSL_get_peer_certificate(ssl)) && host)
  	foo=SSL_get_verify_result(ssl);
  if ((X509_V_OK==foo) || X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN==foo))
```
// certificate looks good, host can be trusted*
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-296

  • Architecture and Design Ensure that proper certificate checking is included in the system design.
  • Implementation Understand, and properly implement all checks necessary to ensure the integrity of certificate trust integrity.
  • Implementation If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the full chain of trust.
Sinais de deteção

How to detect CWE-296

Automated Static Analysis High

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.)

Correção automática do Plexicus

O Plexicus deteta automaticamente o CWE-296 e abre um PR de correção em menos de 60 segundos.

O Codex Remedium analisa cada commit, identifica esta fraqueza exata e entrega um pull request pronto para revisão com o patch. Sem tickets. Sem transferências.

Obter uma demonstração Experimente o Plexicus gratuitamente
Perguntas frequentes

Frequently asked questions

O que é o CWE-296?

This vulnerability occurs when software fails to properly validate the entire certificate chain back to a trusted root authority. This mistake can cause the system to incorrectly trust a certificate and the resource it represents, creating a security gap.

Qual a gravidade do CWE-296?

A MITRE classifica a probabilidade de exploração como Baixa — a exploração é pouco comum, mas a fraqueza deve mesmo assim ser corrigida quando descoberta.

Que linguagens ou plataformas são afetadas pelo CWE-296?

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

Como posso prevenir o CWE-296?

Ensure that proper certificate checking is included in the system design. Understand, and properly implement all checks necessary to ensure the integrity of certificate trust integrity.

Como é que o Plexicus deteta e corrige o CWE-296?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-296 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-296?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/296.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-296

CWE-295 Pai

Improper Certificate Validation

This vulnerability occurs when an application fails to properly verify the authenticity of a digital certificate, or performs the…

CWE-297 Irmão

Improper Validation of Certificate with Host Mismatch

This vulnerability occurs when an application accepts a valid SSL/TLS certificate without properly verifying that it actually belongs to…

CWE-298 Irmão

Improper Validation of Certificate Expiration

This vulnerability occurs when an application fails to properly check if a digital certificate has expired, potentially trusting…

CWE-299 Irmão

Improper Check for Certificate Revocation

This vulnerability occurs when an application fails to properly verify whether a security certificate has been revoked, potentially…

CWE-599 Irmão

Missing Validation of OpenSSL Certificate

This vulnerability occurs when an application uses OpenSSL but fails to properly verify server certificates by not calling…

Recursos

Further reading

Pronto quando você estiver

Pare de pagar por desenvolvedor.
Comece a fechar o ciclo.

O Plexicus é o ASPM nativo de IA que verifica, filtra, corrige, pentesta e explica — de forma autónoma. Programadores ilimitados, repos ilimitados, ações de IA de utilização justa. Nível gratuito real, €269/mo anual quando estiver pronto.

Começar grátis Reservar uma demo