CWE-257 Base Incompleto High likelihood

Storing Passwords in a Recoverable Format

This vulnerability occurs when an application stores user passwords in a format that can be easily reversed or decrypted back to their original plaintext form. This practice, often called storing…

Definición

What is CWE-257?

This vulnerability occurs when an application stores user passwords in a format that can be easily reversed or decrypted back to their original plaintext form. This practice, often called storing 'recoverable' passwords, defeats the core purpose of password protection. It allows anyone with access to the stored data—including attackers who breach the system or even malicious insiders—to obtain and reuse the actual passwords on other accounts, offering no real security advantage over storing them in plain text.
When passwords are stored in a recoverable format, such as using weak or reversible encryption instead of a proper one-way hash, the system inherently retains the ability to convert them back. This creates a single point of failure: if the storage is compromised or accessed by an unauthorized party, every password becomes immediately usable for account takeover and credential stuffing attacks across other services. The risk is identical to storing plaintext passwords, as the decryption key or method is typically accessible within the application's environment. From a security perspective, there is no legitimate operational need for developers or system administrators to retrieve a user's original password. Standard authentication should compare a one-way hash of the entered password against a stored hash. Any design that requires password recovery is flawed; a secure system should only offer a password reset function. Relying on reversible storage undermines user trust and system integrity, as it enables abuse by both external attackers and privileged insiders who can decrypt credentials at will.
Impacto en el mundo real

Real-world CVEs caused by CWE-257

  • A messaging platform serializes all elements of User/Group objects, making private information available to adversaries

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    Both of these examples verify a password by comparing it to a stored compressed version.

  2. 2

    Because a compression algorithm is used instead of a one way hashing algorithm, an attacker can recover compressed passwords stored in the database.

  3. 3

    The following examples show a portion of properties and configuration files for Java and ASP.NET applications. The files include username and password information but they are stored in cleartext.

  4. 4

    This Java example shows a properties file with a cleartext username / password pair.

  5. 5

    The following example shows a portion of a configuration file for an ASP.Net application. This configuration file includes username and password information for a connection to a database but the pair is stored in cleartext.

Ejemplo de código vulnerable

Vulnerable C

Both of these examples verify a password by comparing it to a stored compressed version.

Vulnerable C
int VerifyAdmin(char *password) {
  	if (strcmp(compress(password), compressed_password)) {
  		printf("Incorrect Password!\n");
  		return(0);
  	}
  	printf("Entering Diagnostic Mode...\n");
  	return(1);
  }
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-257

  • Architecture and Design Use strong, non-reversible encryption to protect stored passwords.
Señales de detección

How to detect CWE-257

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.)

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-257 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

Frequently asked questions

¿Qué es CWE-257?

This vulnerability occurs when an application stores user passwords in a format that can be easily reversed or decrypted back to their original plaintext form. This practice, often called storing 'recoverable' passwords, defeats the core purpose of password protection.

¿Qué gravedad tiene CWE-257?

MITRE califica la probabilidad de explotación como Alta — esta debilidad se explota activamente en la práctica y debe priorizarse para su remediación.

¿Qué lenguajes o plataformas se ven afectados por CWE-257?

MITRE no ha especificado plataformas afectadas para esta CWE — puede aplicar a la mayoría de los stacks de aplicaciones.

¿Cómo puedo prevenir CWE-257?

Use strong, non-reversible encryption to protect stored passwords.

¿Cómo detecta y corrige Plexicus CWE-257?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-257 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-257?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/257.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

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