CWE-290 Base Incompleto

Authentication Bypass by Spoofing

This weakness occurs when an application's authentication system can be tricked into accepting forged or manipulated credentials, allowing unauthorized access without proper verification.

Definição

What is CWE-290?

This weakness occurs when an application's authentication system can be tricked into accepting forged or manipulated credentials, allowing unauthorized access without proper verification.
Authentication bypass by spoofing happens when an application fails to properly verify the source or integrity of authentication data. Instead of robustly checking credentials, the system might accept falsified information from network packets, certificates, session tokens, or identity claims. This allows attackers to impersonate legitimate users by crafting fake authentication artifacts that the flawed validation logic incorrectly approves. Common root causes include trusting easily forged data like IP addresses or HTTP headers for identity, using weak cryptographic signatures, or failing to validate the entire authentication chain. To prevent this, developers must implement complete credential verification using cryptographically secure methods, never rely on client-supplied data alone for identity, and ensure all authentication tokens are properly signed and validated on the server side.
Impacto no mundo real

Real-world CVEs caused by CWE-290

  • CVE-2022-30319

    S-bus functionality in a home automation product performs access control using an IP allowlist, which can be bypassed by a forged IP address.

  • CVE-2009-1048

    VOIP product allows authentication bypass using 127.0.0.1 in the Host header.

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    The following code authenticates users.

  2. 2

    The authentication mechanism implemented relies on an IP address for source validation. If an attacker is able to spoof the IP, they may be able to bypass the authentication mechanism.

  3. 3

    Both of these examples check if a request is from a trusted address before responding to the request.

  4. 4

    The code only verifies the address as stored in the request packet. An attacker can spoof this address, thus impersonating a trusted client.

  5. 5

    The following code samples use a DNS lookup in order to decide whether or not an inbound request is from a trusted host. If an attacker can poison the DNS cache, they can gain trusted status.

Exemplo de código vulnerável

Vulnerable Java

The following code authenticates users.

Vulnerável Java 
String sourceIP = request.getRemoteAddr();
  if (sourceIP != null && sourceIP.equals(APPROVED_IP)) {
  	authenticated = true;
  }
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-290

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Sinais de deteção

How to detect CWE-290

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.

Correção automática do Plexicus

O Plexicus deteta automaticamente o CWE-290 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.

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Perguntas frequentes

Frequently asked questions

O que é o CWE-290?

This weakness occurs when an application's authentication system can be tricked into accepting forged or manipulated credentials, allowing unauthorized access without proper verification.

Qual a gravidade do CWE-290?

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-290?

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

Como posso prevenir o CWE-290?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

Como é que o Plexicus deteta e corrige o CWE-290?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-290 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-290?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/290.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-290

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Password Aging with Long Expiration

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CWE-289 Irmão

Authentication Bypass by Alternate Name

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CWE-294 Irmão

Authentication Bypass by Capture-replay

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CWE-301 Irmão

Reflection Attack in an Authentication Protocol

A reflection attack is a flaw in mutual authentication protocols that allows an attacker to impersonate a legitimate user without knowing…

CWE-302 Irmão

Authentication Bypass by Assumed-Immutable Data

This vulnerability occurs when an authentication system incorrectly treats certain data as unchangeable, when in fact an attacker can…

CWE-303 Irmão

Incorrect Implementation of Authentication Algorithm

This weakness occurs when a developer implements a standard authentication algorithm, but makes critical mistakes in the code that cause…

Recursos

Further reading

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