CWE-200 Classe Rascunho High likelihood

Exposure of Sensitive Information to an Unauthorized Actor

This weakness occurs when an application unintentionally reveals sensitive data to someone who shouldn't have access to it.

Definição

What is CWE-200?

This weakness occurs when an application unintentionally reveals sensitive data to someone who shouldn't have access to it.
An information exposure happens when sensitive data leaks from your system. This can include personal user details like financial or health information, internal system data such as configuration or logs, business secrets, or even metadata about your application's operations. The leak can be direct, like accidentally including private data in an error message, or indirect, where another vulnerability allows unauthorized access to protected resources. The impact depends heavily on what's exposed and who sees it. Different parties—end users, administrators, or third parties—have different expectations of privacy. While many vulnerabilities can lead to data leaks, this specific weakness focuses on errors in how the code itself handles, transmits, or sanitizes sensitive information, rather than broader access control failures.
Impacto no mundo real

Real-world CVEs caused by CWE-200

  • Rust library leaks Oauth client details in application debug logs

  • Digital Rights Management (DRM) capability for mobile platform leaks pointer information, simplifying ASLR bypass

  • Enumeration of valid usernames based on inconsistent responses

  • Account number enumeration via inconsistent responses.

  • User enumeration via discrepancies in error messages.

  • Telnet protocol allows servers to obtain sensitive environment information from clients.

  • Script calls phpinfo(), revealing system configuration to web user

  • Product sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    The following code checks validity of the supplied username and password and notifies the user of a successful or failed login.

  2. 2

    In the above code, there are different messages for when an incorrect username is supplied, versus when the username is correct but the password is wrong. This difference enables a potential attacker to understand the state of the login function, and could allow an attacker to discover a valid username by trying different values until the incorrect password message is returned. In essence, this makes it easier for an attacker to obtain half of the necessary authentication credentials.

  3. 3

    While this type of information may be helpful to a user, it is also useful to a potential attacker. In the above example, the message for both failed cases should be the same, such as:

  4. 4

    This code tries to open a database connection, and prints any exceptions that occur.

  5. 5

    If an exception occurs, the printed message exposes the location of the configuration file the script is using. An attacker can use this information to target the configuration file (perhaps exploiting a Path Traversal weakness). If the file can be read, the attacker could gain credentials for accessing the database. The attacker may also be able to replace the file with a malicious one, causing the application to use an arbitrary database.

Exemplo de código vulnerável

Vulnerable Perl

The following code checks validity of the supplied username and password and notifies the user of a successful or failed login.

Vulnerável Perl
my $username=param('username'); 
  my $password=param('password'); 
  if (IsValidUsername($username) == 1) 
  { 
  	if (IsValidPassword($username, $password) == 1) 
  	{ 
  		print "Login Successful"; 
  	} 
  	else 
  	{ 
  		print "Login Failed - incorrect password"; 
  	} 
  } 
  else 
  { 
  	print "Login Failed - unknown username"; 
  }
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-200

  • Architecture and Design Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Sinais de deteção

How to detect CWE-200

Automated Static Analysis - Binary or Bytecode SOAR Partial

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Bytecode Weakness Analysis - including disassembler + source code weakness analysis Inter-application Flow Analysis

Dynamic Analysis with Automated Results Interpretation High

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Web Application Scanner Web Services Scanner Database Scanners

Dynamic Analysis with Manual Results Interpretation SOAR Partial

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Fuzz Tester Framework-based Fuzzer Automated Monitored Execution Monitored Virtual Environment - run potentially malicious code in sandbox / wrapper / virtual machine, see if it does anything suspicious

Manual Static Analysis - Source Code High

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Manual Source Code Review (not inspections)

Automated Static Analysis - Source Code High

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Context-configured Source Code Weakness Analyzer ``` Cost effective for partial coverage: ``` Source code Weakness Analyzer

Architecture or Design Review High

According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Formal Methods / Correct-By-Construction ``` Cost effective for partial coverage: ``` Attack Modeling Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Correção automática do Plexicus

O Plexicus deteta automaticamente o CWE-200 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.

Perguntas frequentes

Frequently asked questions

O que é o CWE-200?

This weakness occurs when an application unintentionally reveals sensitive data to someone who shouldn't have access to it.

Qual a gravidade do CWE-200?

A MITRE classifica a probabilidade de exploração como Alta — esta fraqueza é ativamente explorada em campo e deve ser priorizada para remediação.

Que linguagens ou plataformas são afetadas pelo CWE-200?

MITRE lists the following affected platforms: Mobile.

Como posso prevenir o CWE-200?

Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to…

Como é que o Plexicus deteta e corrige o CWE-200?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-200 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-200?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/200.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

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