Some tools can act as proxy servers that allow the tester to intercept packets or messages, inspect them, and modify them before sending them to the destination in order to see if the modified packets are still accepted by the receiving component.
CWE-300 Clase Borrador
Channel Accessible by Non-Endpoint
This vulnerability occurs when a system fails to properly verify who is on the other end of a communication link or to secure the channel itself. This allows an unauthorized third party to access or…
Definición
What is CWE-300?
This vulnerability occurs when a system fails to properly verify who is on the other end of a communication link or to secure the channel itself. This allows an unauthorized third party to access or manipulate the communication as if they were a legitimate participant.
Secure communication requires confidently knowing who you're talking to at both ends of the connection. If a system performs weak, inconsistent, or missing identity checks, it can't be sure if the other party is genuine. Attackers exploit this gap by inserting themselves into the channel, impersonating a trusted endpoint. Once in the middle, they can silently eavesdrop on or alter the data flowing between the two original, unsuspecting parties.
For developers, the core issue is misplaced trust. Without robust endpoint verification—like mutual authentication—your application might share sensitive data with an impostor. To prevent this, ensure your implementation validates identities at both ends using strong, cryptographic methods and maintains the channel's integrity to block unauthorized access or tampering.
Impacto en el mundo real
Real-world CVEs caused by CWE-300
-
chain: incorrect "goto" in Apple SSL product bypasses certificate validation, allowing Adversry-in-the-Middle (AITM) attack (Apple "goto fail" bug). CWE-705 (Incorrect Control Flow Scoping) -> CWE-561 (Dead Code) -> CWE-295 (Improper Certificate Validation) -> CWE-393 (Return of Wrong Status Code) -> CWE-300 (Channel Accessible by Non-Endpoint).
Cómo lo explotan los atacantes
Ruta del atacante paso a paso
- 1
Identifica una ruta de código que maneje entrada no confiable sin validación.
- 2
Crea un payload que ejercite el comportamiento inseguro — inyección, traversal, overflow o abuso de lógica.
- 3
Envía el payload a través de una solicitud normal y observa la reacción de la aplicación.
- 4
Itera hasta que la respuesta filtre datos, ejecute código del atacante o escale privilegios.
Ejemplo de código vulnerable
Vulnerable Java
In the Java snippet below, data is sent over an unencrypted channel to a remote server.
Socket sock;
PrintWriter out;
try {
sock = new Socket(REMOTE_HOST, REMOTE_PORT);
out = new PrintWriter(echoSocket.getOutputStream(), true);
```
// Write data to remote host via socket output stream.*
...} 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-300
- Implementation Always fully authenticate both ends of any communications channel.
- Architecture and Design Adhere to the principle of complete mediation.
- Implementation A certificate binds an identity to a cryptographic key to authenticate a communicating party. Often, the certificate takes the encrypted form of the hash of the identity of the subject, the public key, and information such as time of issue or expiration using the issuer's private key. The certificate can be validated by deciphering the certificate with the issuer's public key. See also X.509 certificate signature chains and the PGP certification structure.
Señales de detección
How to detect CWE-300
Dynamic Application Security Testing (DAST) tools can be used to detect network traffic without encryption and/or verification. The affected protocol may be subject to Adversary-in-the-Middle attacks. Some tools act as proxy servers that allow the tester to inspect and modify packets/messages to see if they are still accepted by the receiving component.
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.) The analysis could identify use of protocols that are subject to Adversary-in-the-Middle attacks.
Plexicus detecta automáticamente CWE-300 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-300?
¿Qué gravedad tiene CWE-300?
¿Qué lenguajes o plataformas se ven afectados por CWE-300?
¿Cómo puedo prevenir CWE-300?
¿Cómo detecta y corrige Plexicus CWE-300?
¿Dónde puedo aprender más sobre CWE-300?
Frequently asked questions
¿Qué es CWE-300?
This vulnerability occurs when a system fails to properly verify who is on the other end of a communication link or to secure the channel itself. This allows an unauthorized third party to access or manipulate the communication as if they were a legitimate participant.
¿Qué gravedad tiene CWE-300?
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-300?
MITRE no ha especificado plataformas afectadas para esta CWE — puede aplicar a la mayoría de los stacks de aplicaciones.
¿Cómo puedo prevenir CWE-300?
Always fully authenticate both ends of any communications channel. Adhere to the principle of complete mediation.
¿Cómo detecta y corrige Plexicus CWE-300?
El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-300 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-300?
MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/300.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.
Debilidades relacionadas
Weaknesses related to CWE-300
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CWE-297 Hermano
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CWE-941 Hermano
Incorrectly Specified Destination in a Communication Channel
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Permissive Cross-domain Security Policy with Untrusted Domains
This vulnerability occurs when a web application's cross-domain security policy, like a Content Security Policy (CSP), explicitly allows…
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