CWE-943 Classe Incompleto

Improper Neutralization of Special Elements in Data Query Logic

This vulnerability occurs when an application builds a query for a data store (like a database) but fails to properly sanitize user-controlled input. This allows an attacker to inject special…

Definição

What is CWE-943?

This vulnerability occurs when an application builds a query for a data store (like a database) but fails to properly sanitize user-controlled input. This allows an attacker to inject special elements that change the query's intended logic, potentially accessing or manipulating data in unauthorized ways.
Attackers can exploit this flaw to manipulate query logic in several harmful ways. They can alter search criteria to return different records, append extra commands, or change the number or order of results. This isn't just about stealing data; if your application logic assumes a specific result—like a single administrative user record—manipulating the query can cause it to incorrectly grant permissions or make flawed decisions based on tainted results. While SQL injection is the most well-known example, this risk applies to many query languages. NoSQL databases, LDAP queries, XPath, and other data querying systems (like HTSQL, DQL, or XQuery) are also vulnerable if input isn't properly neutralized. The core issue is trusting user input within any command that interprets logic, not just traditional SQL.
Impacto no mundo real

Real-world CVEs caused by CWE-943

  • CVE-2024-50672

    NoSQL injection in product for building eLearning courses allows password resets using a query processed by the Mongoose find function

  • CVE-2021-20736

    NoSQL injection in team collaboration product

  • CVE-2020-35666

    NoSQL injection in a PaaS platform using a MongoDB operator

  • CVE-2014-2503

    Injection using Documentum Query Language (DQL)

  • CVE-2014-2508

    Injection using Documentum Query Language (DQL)

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    The following code dynamically constructs and executes a SQL query that searches for items matching a specified name. The query restricts the items displayed to those where owner matches the user name of the currently-authenticated user.

  2. 2

    The query that this code intends to execute follows:

  3. 3

    However, because the query is constructed dynamically by concatenating a constant base query string and a user input string, the query only behaves correctly if itemName does not contain a single-quote character. If an attacker with the user name wiley enters the string:

  4. 4

    for itemName, then the query becomes the following:

  5. 5

    The addition of the:

Exemplo de código vulnerável

Vulnerable C#

The following code dynamically constructs and executes a SQL query that searches for items matching a specified name. The query restricts the items displayed to those where owner matches the user name of the currently-authenticated user.

Vulnerável C# 
...
  string userName = ctx.getAuthenticatedUserName();
  string query = "SELECT * FROM items WHERE owner = '" + userName + "' AND itemname = '" + ItemName.Text + "'";
  sda = new SqlDataAdapter(query, conn);
  DataTable dt = new DataTable();
  sda.Fill(dt);
  ...
Payload do atacante

However, because the query is constructed dynamically by concatenating a constant base query string and a user input string, the query only behaves correctly if itemName does not contain a single-quote character. If an attacker with the user name wiley enters the string:

Payload do atacante 
name' OR 'a'='a
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-943

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Sinais de deteção

How to detect CWE-943

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.)

Correção automática do Plexicus

O Plexicus deteta automaticamente o CWE-943 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.

Obter uma demonstração Experimente o Plexicus gratuitamente
Perguntas frequentes

Frequently asked questions

O que é o CWE-943?

This vulnerability occurs when an application builds a query for a data store (like a database) but fails to properly sanitize user-controlled input. This allows an attacker to inject special elements that change the query's intended logic, potentially accessing or manipulating data in unauthorized ways.

Qual a gravidade do CWE-943?

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-943?

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

Como posso prevenir o CWE-943?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

Como é que o Plexicus deteta e corrige o CWE-943?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-943 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-943?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/943.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-943

CWE-74 Pai

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

This vulnerability occurs when an application uses untrusted external input to build a command, query, or data structure for another…

CWE-1236 Irmão

Improper Neutralization of Formula Elements in a CSV File

This vulnerability occurs when an application writes user-supplied data into a CSV file without properly sanitizing special characters.…

CWE-75 Irmão

Failure to Sanitize Special Elements into a Different Plane (Special Element Injection)

This vulnerability occurs when an application fails to properly filter or encode user-supplied data containing special characters or…

CWE-77 Irmão

Improper Neutralization of Special Elements used in a Command ('Command Injection')

This vulnerability occurs when an application builds a system command using untrusted user input without properly sanitizing it. An…

CWE-78 Irmão

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

OS Command Injection occurs when an application builds a system command using untrusted, external input without properly sanitizing it.…

CWE-79 Irmão

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

This vulnerability occurs when a web application fails to properly sanitize or encode user-supplied input before displaying it on a…

CWE-88 Irmão

Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')

This vulnerability occurs when an application builds a command string for execution by another component, but fails to properly separate…

CWE-89 Irmão

Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

SQL Injection occurs when an application builds a database query using untrusted user input without properly sanitizing it. This allows an…

CWE-91 Irmão

XML Injection (aka Blind XPath Injection)

XML Injection occurs when an application fails to properly validate or escape user-controlled input before including it in XML documents…

Recursos

Further reading

Pronto quando você estiver

Pare de pagar por desenvolvedor.
Comece a fechar o ciclo.

O Plexicus é o ASPM nativo de IA que verifica, filtra, corrige, pentesta e explica — de forma autónoma. Programadores ilimitados, repos ilimitados, ações de IA de utilização justa. Nível gratuito real, €269/mo anual quando estiver pronto.

Começar grátis Reservar uma demo