CWE-537 Variante Incompleto

Java Runtime Error Message Containing Sensitive Information

This vulnerability occurs when a Java application's runtime error messages reveal sensitive details about the system, such as file paths, internal IP addresses, or stack traces. Attackers can…

Definición

What is CWE-537?

This vulnerability occurs when a Java application's runtime error messages reveal sensitive details about the system, such as file paths, internal IP addresses, or stack traces. Attackers can exploit these overly informative error messages to map the application's structure and gather intelligence for further attacks.
When an unhandled exception occurs, the default behavior in many Java applications is to display a detailed error message to the user. These messages often contain internal data like server file system paths, database connection strings, library versions, or configuration details. This information is invaluable to an attacker, as it helps them understand the underlying technology stack and pinpoint weaknesses without needing to probe the system directly. To prevent this, developers should implement a global exception handler that catches all unhandled exceptions and replaces verbose system-generated messages with generic, user-friendly ones. All detailed error information should be logged securely on the server side for debugging purposes, never exposed to the end-user. This practice, often called 'security through obscurity,' is a critical layer in a defense-in-depth strategy, ensuring that failures don't inadvertently hand attackers a roadmap to your system.
Impacto en el mundo real

Real-world CVEs caused by CWE-537

Todavía no hay CVEs públicos enlazados a esta CWE en el catálogo de MITRE.

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    In the following Java example the class InputFileRead enables an input file to be read using a FileReader object. In the constructor of this class a default input file path is set to some directory on the local file system and the method setInputFile must be called to set the name of the input file to be read in the default directory. The method readInputFile will create the FileReader object and will read the contents of the file. If the method setInputFile is not called prior to calling the method readInputFile then the File object will remain null when initializing the FileReader object. A Java RuntimeException will be raised, and an error message will be output to the user.

  2. 2

    However, the error message output to the user contains information regarding the default directory on the local file system. This information can be exploited and may lead to unauthorized access or use of the system. Any Java RuntimeExceptions that are handled should not expose sensitive information to the user.

  3. 3

    In the example below, the BankManagerLoginServlet servlet class will process a login request to determine if a user is authorized to use the BankManager Web service. The doPost method will retrieve the username and password from the servlet request and will determine if the user is authorized. If the user is authorized the servlet will go to the successful login page. Otherwise, the servlet will raise a FailedLoginException and output the failed login message to the error page of the service.

  4. 4

    However, the output message generated by the FailedLoginException includes the user-supplied password. Even if the password is erroneous, it is probably close to the correct password. Since it is printed to the user's page, anybody who can see the screen display will be able to see the password. Also, if the page is cached, the password might be written to disk.

Ejemplo de código vulnerable

Vulnerable Java

In the following Java example the class InputFileRead enables an input file to be read using a FileReader object. In the constructor of this class a default input file path is set to some directory on the local file system and the method setInputFile must be called to set the name of the input file to be read in the default directory. The method readInputFile will create the FileReader object and will read the contents of the file. If the method setInputFile is not called prior to calling the method readInputFile then the File object will remain null when initializing the FileReader object. A Java RuntimeException will be raised, and an error message will be output to the user.

Vulnerable Java 
public class InputFileRead {
  		private File readFile = null;
  		private FileReader reader = null;
  		private String inputFilePath = null;
  		private final String DEFAULT_FILE_PATH = "c:\\somedirectory\\";
  		public InputFileRead() {
  			inputFilePath = DEFAULT_FILE_PATH;
  		}
  		public void setInputFile(String inputFile) {
```
/* Assume appropriate validation / encoding is used and privileges / permissions are preserved */* 
  				}
  		
  		public void readInputFile() {
  		```
  				try {
  					reader = new FileReader(readFile);
  					...
  				} catch (RuntimeException rex) {
  					System.err.println("Error: Cannot open input file in the directory " + inputFilePath);
  					System.err.println("Input file has not been set, call setInputFile method before calling readInputFile");
  				} catch (FileNotFoundException ex) {...}
  		}
  }
Ejemplo 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 prevención

How to prevent CWE-537

  • Implementation Do not expose sensitive error information to the user.
Señales de detección

How to detect CWE-537

SAST High

Ejecuta análisis estático (SAST) sobre el código buscando el patrón inseguro en el flujo de datos.

DAST Moderate

Ejecuta pruebas dinámicas de seguridad de aplicaciones (DAST) contra el endpoint en vivo.

Runtime Moderate

Vigila los logs en tiempo de ejecución para detectar trazas de excepción inusuales, entradas malformadas o intentos de bypass de autorización.

Code review Moderate

Revisión de código: marca cualquier código nuevo que maneje entrada desde esta superficie sin usar los helpers validados del framework.

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-537 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.

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Preguntas frecuentes

Frequently asked questions

¿Qué es CWE-537?

This vulnerability occurs when a Java application's runtime error messages reveal sensitive details about the system, such as file paths, internal IP addresses, or stack traces. Attackers can exploit these overly informative error messages to map the application's structure and gather intelligence for further attacks.

¿Qué gravedad tiene CWE-537?

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-537?

MITRE lists the following affected platforms: Java.

¿Cómo puedo prevenir CWE-537?

Do not expose sensitive error information to the user.

¿Cómo detecta y corrige Plexicus CWE-537?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-537 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-537?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/537.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-537

CWE-211 Padre

Externally-Generated Error Message Containing Sensitive Information

This vulnerability occurs when an application triggers an error message from an external component—like a database, interpreter, or…

CWE-535 Hermano

Exposure of Information Through Shell Error Message

This vulnerability occurs when a web application's command shell returns detailed error messages to users. Attackers can analyze these…

CWE-536 Hermano

Servlet Runtime Error Message Containing Sensitive Information

This vulnerability occurs when a Java servlet application displays detailed runtime error messages that reveal sensitive information about…

Recursos

Further reading

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