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-943 Clase 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…
Definición
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 en el mundo real
Real-world CVEs caused by CWE-943
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NoSQL injection in product for building eLearning courses allows password resets using a query processed by the Mongoose find function
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NoSQL injection in team collaboration product
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NoSQL injection in a PaaS platform using a MongoDB operator
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Injection using Documentum Query Language (DQL)
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Injection using Documentum Query Language (DQL)
Cómo lo explotan los atacantes
Ruta del atacante paso a paso
- 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
The query that this code intends to execute follows:
- 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
for itemName, then the query becomes the following:
- 5
The addition of the:
Ejemplo de código vulnerable
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.
...
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 del 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:
name' OR 'a'='a Ejemplo de código seguro
Secure 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 prevención
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.
Señales de detección
How to detect CWE-943
Plexicus detecta automáticamente CWE-943 y abre un PR de corrección en menos de 60 segundos.
Codex Remedium escanea cada commit, identifica esta debilidad concreta y entrega un pull request listo para revisión con el parche. Sin tickets. Sin traspasos.
Preguntas frecuentes ¿Qué es CWE-943?
¿Qué gravedad tiene CWE-943?
¿Qué lenguajes o plataformas se ven afectados por CWE-943?
¿Cómo puedo prevenir CWE-943?
¿Cómo detecta y corrige Plexicus CWE-943?
¿Dónde puedo aprender más sobre CWE-943?
Frequently asked questions
¿Qué es 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.
¿Qué gravedad tiene CWE-943?
MITRE no ha publicado una calificación de probabilidad de explotación para esta debilidad. Trátala como de impacto medio hasta que tu modelo de amenazas demuestre lo contrario.
¿Qué lenguajes o plataformas se ven afectados por CWE-943?
MITRE no ha especificado plataformas afectadas para esta CWE — puede aplicar a la mayoría de los stacks de aplicaciones.
¿Cómo puedo prevenir 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.
¿Cómo detecta y corrige Plexicus CWE-943?
El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-943 en cada commit. Cuando hay coincidencia, nuestro agente Codex Remedium abre un PR de corrección con el código corregido, las pruebas y un resumen de una línea para el revisor.
¿Dónde puedo aprender más sobre CWE-943?
MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/943.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.
Debilidades relacionadas
Weaknesses related to CWE-943
CWE-74 Padre
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 Hermano
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 Hermano
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 Hermano
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 Hermano
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 Hermano
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 Hermano
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 Hermano
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 Hermano
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…
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