CWE-178 Base Incompleto

Improper Handling of Case Sensitivity

This vulnerability occurs when software fails to consistently handle uppercase and lowercase letters when checking or accessing resources, leading to unpredictable behavior and security gaps.

Definição

What is CWE-178?

This vulnerability occurs when software fails to consistently handle uppercase and lowercase letters when checking or accessing resources, leading to unpredictable behavior and security gaps.
When an application treats 'Admin', 'admin', and 'ADMIN' as different entities, it creates inconsistencies that attackers can exploit. For example, a filter blocking 'admin.php' might be bypassed by requesting 'Admin.PHP', or a system might create duplicate user accounts with only case differences, corrupting data integrity. From a security perspective, mishandling case sensitivity weakens defenses. It can drastically reduce password complexity by making 'Password' equivalent to 'password', simplifying brute-force attacks. It also allows attackers to evade security checks by using alternate capitalizations to access restricted files or bypass input validation rules.
Impacto no mundo real

Real-world CVEs caused by CWE-178

  • CVE-2000-0499

    Application server allows attackers to bypass execution of a jsp page and read the source code using an upper case JSP extension in the request.

  • CVE-2000-0497

    The server is case sensitive, so filetype handlers treat .jsp and .JSP as different extensions. JSP source code may be read because .JSP defaults to the filetype "text".

  • CVE-2000-0498

    The server is case sensitive, so filetype handlers treat .jsp and .JSP as different extensions. JSP source code may be read because .JSP defaults to the filetype "text".

  • CVE-2001-0766

    A URL that contains some characters whose case is not matched by the server's filters may bypass access restrictions because the case-insensitive file system will then handle the request after it bypasses the case sensitive filter.

  • CVE-2001-0795

    Server allows remote attackers to obtain source code of CGI scripts via URLs that contain MS-DOS conventions such as (1) upper case letters or (2) 8.3 file names.

  • CVE-2001-1238

    Task Manager does not allow local users to end processes with uppercase letters named (1) winlogon.exe, (2) csrss.exe, (3) smss.exe and (4) services.exe via the Process tab which could allow local users to install Trojan horses that cannot be stopped.

  • CVE-2003-0411

    chain: Code was ported from a case-sensitive Unix platform to a case-insensitive Windows platform where filetype handlers treat .jsp and .JSP as different extensions. JSP source code may be read because .JSP defaults to the filetype "text".

  • CVE-2002-0485

    Leads to interpretation error

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 XSS neutralization method intends to replace script tags in user-supplied input with a safe equivalent:

Vulnerável Java 
public String preventXSS(String input, String mask) {
  	return input.replaceAll("script", mask);
  }
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-178

  • Architecture and Design Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
  • 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 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-178

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-178 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-178?

This vulnerability occurs when software fails to consistently handle uppercase and lowercase letters when checking or accessing resources, leading to unpredictable behavior and security gaps.

Qual a gravidade do CWE-178?

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-178?

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

Como posso prevenir o CWE-178?

Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names. 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…

Como é que o Plexicus deteta e corrige o CWE-178?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-178 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-178?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/178.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-178

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CWE-22 Irmão

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This vulnerability occurs when an application builds a file path using user input but fails to properly validate it, allowing an attacker…

CWE-386 Irmão

Symbolic Name not Mapping to Correct Object

This vulnerability occurs when a program uses a fixed symbolic name (like a constant or identifier) to refer to an object, but that name…

CWE-41 Irmão

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CWE-59 Irmão

Improper Link Resolution Before File Access ('Link Following')

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CWE-66 Irmão

Improper Handling of File Names that Identify Virtual Resources

This vulnerability occurs when software incorrectly processes a filename that points to a 'virtual' resource—like a device, pipe, or…

CWE-827 Irmão

Improper Control of Document Type Definition

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CWE-98 Irmão

Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')

This vulnerability occurs when a PHP application uses unvalidated or insufficiently restricted user input directly within file inclusion…

CWE-433 Pode preceder

Unparsed Raw Web Content Delivery

This vulnerability occurs when a web application stores unprocessed files—like configuration scripts or raw source code—in publicly…

Recursos

Further reading

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