CWE-302 Base Incompleto

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 manipulate it to bypass login or verification checks.

Definição

What is CWE-302?

This vulnerability occurs when an authentication system incorrectly treats certain data as unchangeable, when in fact an attacker can manipulate it to bypass login or verification checks.
Developers often assume that specific data points, like hidden form fields, environment variables, or certain HTTP headers, are secure and cannot be altered by a user. However, attackers can intercept and modify this 'assumed-immutable' data during transit or exploit client-side controls, tricking the application into granting unauthorized access. To prevent this, never trust client-side data for critical security decisions. Always re-validate authentication state and user permissions on the server using a trusted, server-controlled session mechanism. Treat all data from the client—including cookies, headers, and hidden parameters—as potentially malicious and subject to verification against the authoritative server-side session store.
Impacto no mundo real

Real-world CVEs caused by CWE-302

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 Java

In the following example, an "authenticated" cookie is used to determine whether or not a user should be granted access to a system.

Vulnerável Java
boolean authenticated = new Boolean(getCookieValue("authenticated")).booleanValue();
  if (authenticated) {
  	...
  }
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-302

  • Architecture and Design / Operation / Implementation Implement proper protection for immutable data (e.g. environment variable, hidden form fields, etc.)
Sinais de deteção

How to detect CWE-302

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-302

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Perguntas frequentes

Frequently asked questions

O que é o CWE-302?

This vulnerability occurs when an authentication system incorrectly treats certain data as unchangeable, when in fact an attacker can manipulate it to bypass login or verification checks.

Qual a gravidade do CWE-302?

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-302?

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

Como posso prevenir o CWE-302?

Implement proper protection for immutable data (e.g. environment variable, hidden form fields, etc.)

Como é que o Plexicus deteta e corrige o CWE-302?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-302 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-302?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/302.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-302

CWE-1390 Pai

Weak Authentication

This vulnerability occurs when a system's login or identity verification process is too easy to bypass or fool. While it attempts to check…

CWE-1391 Irmão

Use of Weak Credentials

This vulnerability occurs when a system relies on weak authentication credentials—like default passwords, hard-coded keys, or easily…

CWE-262 Irmão

Not Using Password Aging

This vulnerability occurs when a system lacks password expiration policies, allowing users to keep the same password indefinitely.

CWE-263 Irmão

Password Aging with Long Expiration

The system enforces password changes, but the time allowed between changes is excessively long, weakening security.

CWE-289 Irmão

Authentication Bypass by Alternate Name

This vulnerability occurs when a system checks access based on a resource or user name, but fails to account for all the different names…

CWE-290 Irmão

Authentication Bypass by Spoofing

This weakness occurs when an application's authentication system can be tricked into accepting forged or manipulated credentials, allowing…

CWE-294 Irmão

Authentication Bypass by Capture-replay

This vulnerability occurs when an attacker can intercept and record legitimate authentication traffic, then replay it later to gain…

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-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…

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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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