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…

Definição

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 no 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

Como os atacantes a exploram

Trajeto do atacante passo a passo

  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.

Exemplo de código vulnerável

Vulnerable C

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

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

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

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.)

CWE-257

Don't catalog this weakness. Prove it's reachable.

Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.

Perguntas frequentes

Frequently asked questions

O que é o 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.

Qual a gravidade do CWE-257?

A MITRE classifica a probabilidade de exploração como Alta — esta fraqueza é ativamente explorada em campo e deve ser priorizada para remediação.

Que linguagens ou plataformas são afetadas pelo CWE-257?

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

Como posso prevenir o CWE-257?

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

Como é que o Plexicus deteta e corrige o CWE-257?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-257 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-257?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/257.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Pronto para validar o que importa?

Pronto para validar o que importa.

O Plexicus é Proof-Driven AppSec: achados validados, compreensão contextual e remediação revisada — ancorada em evidência, escopada com você.

Qualificação

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SAMPLE HANDOVER · ILLUSTRATIVE

Sample evidence handover

A trimmed view of what your team receives at the end of an AI Swarm Pentest engagement. Real engagements include full technical evidence, executive narrative, and a remediation plan.

VALIDATED FINDING Evidence attached

Server-Side Request Forgery in webhooks/receiver

demo-project/sample-app · src/webhooks/receiver.py:42

SeverityHigh CVSS 3.18.6 Priority79 Confirmedvia replay

Untrusted caller-supplied URLs reach an internal egress without an allowlist. Replayed in a sandbox against a fresh authorized target — the same control was validated to fail twice.

REVIEWER-READY REMEDIATION Merge-ready PR

Validate the target URL against an allowlist of permitted hostnames. Reject private/internal IP ranges. Enforce HTTPS only.

plexicus/remediation/webhooks-ssrf 3 changed · 0 new files
42resp = requests.get(target_url)
42+if not is_allowed_host(target_url):
43+  raise WebhookRejected(target_url)
44+resp = requests.get(target_url, timeout=5)
Every engagement hands over:
  • Executive briefing
  • Validated findings list
  • Merge-ready PRs
  • Compliance mapping (NIS2 · DORA · CRA)
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