CWE-548: Exposure of Information Through Directory Listing

Definição

What is CWE-548?

This vulnerability occurs when a web server is misconfigured to display a full list of files within a directory instead of serving a default web page, unintentionally exposing sensitive resources to anyone who visits the URL.

Directory listings happen when a web server (like Apache, Nginx, or IIS) can't find a default index file (e.g., index.html) and its configuration allows it to show the folder's contents. This acts as a roadmap for attackers, revealing backup files, configuration scripts, temporary uploads, or administrative interfaces that were never meant to be public. A simple manual check or a DAST scan can easily uncover this issue. Prevention involves configuring your server to disable directory listings and always ensuring a default index page exists. For developers, this means checking server configuration files for directives like 'Options -Indexes' in Apache or 'autoindex off' in Nginx. Managing this at scale across hundreds of services is difficult; an ASPM like Plexicus can help you continuously track and automatically flag these misconfigurations across your entire application portfolio.

Impacto no mundo real

Real-world CVEs caused by CWE-548

Ainda não há referências CVE públicas associadas a este CWE no catálogo da MITRE.

Como os atacantes a exploram

Trajeto do atacante passo a passo

1
Identificar um caminho de código que trata input não confiável sem validação.
2
Criar um payload que explora o comportamento inseguro — injeção, traversal, overflow ou abuso de lógica.
3
Entregar o payload através de um pedido normal e observar a reação da aplicação.
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-548

Architecture and Design / System Configuration Recommendations include restricting access to important directories or files by adopting a need to know requirement for both the document and server root, and turning off features such as Automatic Directory Listings that could expose private files and provide information that could be utilized by an attacker when formulating or conducting an attack.

Sinais de deteção

How to detect CWE-548

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.)

CWE-548

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Perguntas frequentes

Frequently asked questions

O que é o CWE-548?

This vulnerability occurs when a web server is misconfigured to display a full list of files within a directory instead of serving a default web page, unintentionally exposing sensitive resources to anyone who visits the URL.

Qual a gravidade do CWE-548?

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-548?

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

Como posso prevenir o CWE-548?

Recommendations include restricting access to important directories or files by adopting a need to know requirement for both the document and server root, and turning off features such as Automatic Directory Listings that could expose private files and provide information that could be utilized by an attacker when formulating or conducting an attack.

Como é que o Plexicus deteta e corrige o CWE-548?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-548 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-548?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/548.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-548

CWE-497 Pai

Exposure of Sensitive System Information to an Unauthorized Control Sphere

This vulnerability occurs when an application unintentionally reveals sensitive details about its underlying system, such as file paths,…

CWE-214 Irmão

Invocation of Process Using Visible Sensitive Information

This vulnerability occurs when a process is started with sensitive data, such as passwords or API keys, passed directly in its…

Recursos

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Exposure of Information Through Directory Listing