CWE-256 Base Incompleto High likelihood

Plaintext Storage of a Password

This vulnerability occurs when an application stores user passwords as readable text instead of using secure, one-way hashing. This insecure practice exposes credentials in memory, files, or…

Definición

What is CWE-256?

This vulnerability occurs when an application stores user passwords as readable text instead of using secure, one-way hashing. This insecure practice exposes credentials in memory, files, or databases where attackers can easily retrieve them.
Storing passwords in plaintext is a critical security failure because it completely bypasses the fundamental purpose of password protection. If an attacker gains access to the storage—through a database breach, a leaked file, or a memory dump—they immediately obtain all user credentials. This often leads to account takeover, data theft, and lateral movement across systems, as users frequently reuse passwords. To prevent this, developers must never store the actual password. Instead, always use a strong, adaptive cryptographic hash function (like Argon2, scrypt, or bcrypt) with a unique salt for each password. This transforms the password into a fixed-length, irreversible string. Even if the hash is exposed, the original password remains computationally infeasible to recover, significantly limiting the damage of a data breach.
Vulnerability Diagram CWE-256
Plaintext Storage of Password User signs up pw="hunter2" users table name | password alice | hunter2 bob | letmein eve | qwerty DB dump → all passwords credential stuffing Passwords must be salted+hashed (bcrypt/argon2), never stored plain.
Impacto en el mundo real

Real-world CVEs caused by CWE-256

  • CVE-2022-30275

    Remote Terminal Unit (RTU) uses a driver that relies on a password stored in plaintext.

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

  1. 1

    The following code reads a password from a properties file and uses the password to connect to a database.

  2. 2

    This code will run successfully, but anyone who has access to config.properties can read the value of password. If a devious employee has access to this information, they can use it to break into the system.

  3. 3

    The following code reads a password from the registry and uses the password to create a new network credential.

  4. 4

    This code will run successfully, but anyone who has access to the registry key used to store the password can read the value of password. If a devious employee has access to this information, they can use it to break into the system

  5. 5

    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.

Ejemplo de código vulnerable

Vulnerable Java

The following code reads a password from a properties file and uses the password to connect to a database.

Vulnerable Java 
...
  Properties prop = new Properties();
  prop.load(new FileInputStream("config.properties"));
  String password = prop.getProperty("password");
  DriverManager.getConnection(url, usr, password);
  ...
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-256

  • Architecture and Design Avoid storing passwords in easily accessible locations.
  • Architecture and Design Consider storing cryptographic hashes of passwords as an alternative to storing in plaintext.
  • A programmer might attempt to remedy the password management problem by obscuring the password with an encoding function, such as base 64 encoding, but this effort does not adequately protect the password because the encoding can be detected and decoded easily.
Señales de detección

How to detect CWE-256

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-256 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-256?

This vulnerability occurs when an application stores user passwords as readable text instead of using secure, one-way hashing. This insecure practice exposes credentials in memory, files, or databases where attackers can easily retrieve them.

¿Qué gravedad tiene CWE-256?

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-256?

MITRE lists the following affected platforms: ICS/OT.

¿Cómo puedo prevenir CWE-256?

Avoid storing passwords in easily accessible locations. Consider storing cryptographic hashes of passwords as an alternative to storing in plaintext.

¿Cómo detecta y corrige Plexicus CWE-256?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-256 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-256?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/256.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-256

CWE-522 Padre

Insufficiently Protected Credentials

This vulnerability occurs when an application handles sensitive credentials like passwords or API keys in an insecure way, making them…

CWE-257 Hermano

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…

CWE-260 Hermano

Password in Configuration File

This vulnerability occurs when an application stores sensitive passwords directly within a configuration file, making them easily readable…

CWE-261 Hermano

Weak Encoding for Password

Using simple encoding like Base64 to hide a password provides no real security, as it can be easily reversed.

CWE-523 Hermano

Unprotected Transport of Credentials

This vulnerability occurs when a login page or authentication system transmits user credentials (like usernames and passwords) over a…

CWE-549 Hermano

Missing Password Field Masking

This vulnerability occurs when an application fails to hide password characters as they are typed, making them visible to anyone who can…

Recursos

Further reading

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