CWE-142 Variante Rascunho

Improper Neutralization of Value Delimiters

This vulnerability occurs when an application fails to properly sanitize or escape special characters that act as data separators (delimiters) before passing that data to another system or…

Definição

What is CWE-142?

This vulnerability occurs when an application fails to properly sanitize or escape special characters that act as data separators (delimiters) before passing that data to another system or component. An attacker can inject these characters to manipulate how the downstream process interprets the data structure.
Think of delimiters like commas in a CSV file or special tags in a data stream—they tell a parser where one piece of information ends and the next begins. If user-supplied input isn't cleaned, an attacker can inject these separator characters. This tricks the receiving component into misreading the data boundaries, often leading to corrupted data, unexpected system behavior, or security breaches like injection attacks. In practice, this flaw breaks the trusted data flow between components. For example, if a web form submits a value that includes an unescaped delimiter used by a backend batch processor, that single input could be split into multiple fake records or commands. To prevent this, developers must rigorously validate and encode all external inputs based on the specific delimiter rules expected by the downstream parser.
Impacto no mundo real

Real-world CVEs caused by CWE-142

  • CVE-2000-0293

    Multiple internal space, insufficient quoting - program does not use proper delimiter between values.

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-142

  • Developers should anticipate that value delimiters will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
  • Implementation Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • Implementation While it is risky to use dynamically-generated query strings, code, or commands that mix control and data together, sometimes it may be unavoidable. Properly quote arguments and escape any special characters within those arguments. The most conservative approach is to escape or filter all characters that do not pass an extremely strict allowlist (such as everything that is not alphanumeric or white space). If some special characters are still needed, such as white space, wrap each argument in quotes after the escaping/filtering step. Be careful of argument injection (CWE-88).
  • Implementation Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
Sinais de deteção

How to detect CWE-142

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-142 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-142?

This vulnerability occurs when an application fails to properly sanitize or escape special characters that act as data separators (delimiters) before passing that data to another system or component. An attacker can inject these characters to manipulate how the downstream process interprets the data structure.

Qual a gravidade do CWE-142?

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-142?

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

Como posso prevenir o CWE-142?

Developers should anticipate that value delimiters will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system. Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications,…

Como é que o Plexicus deteta e corrige o CWE-142?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-142 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-142?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/142.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-142

CWE-140 Pai

Improper Neutralization of Delimiters

This vulnerability occurs when an application fails to properly handle or sanitize delimiter characters within data inputs, allowing them…

CWE-141 Irmão

Improper Neutralization of Parameter/Argument Delimiters

This vulnerability occurs when an application fails to properly sanitize special characters that act as delimiters in data being passed…

CWE-143 Irmão

Improper Neutralization of Record Delimiters

This vulnerability occurs when an application fails to properly sanitize or escape special characters that function as record separators…

CWE-144 Irmão

Improper Neutralization of Line Delimiters

This vulnerability occurs when an application fails to properly sanitize or escape line break characters (like newline or carriage return)…

CWE-145 Irmão

Improper Neutralization of Section Delimiters

This vulnerability occurs when an application fails to properly sanitize or validate special characters that act as section delimiters in…

CWE-146 Irmão

Improper Neutralization of Expression/Command Delimiters

This vulnerability occurs when an application fails to properly sanitize input that contains special characters used as delimiters in…

Recursos

Further reading

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