CWE-927 Variante Incomplet

Use of Implicit Intent for Sensitive Communication

This vulnerability occurs when an Android app uses an implicit intent to send sensitive data, allowing any other app on the device to potentially intercept and read that information.

Définition

What is CWE-927?

This vulnerability occurs when an Android app uses an implicit intent to send sensitive data, allowing any other app on the device to potentially intercept and read that information.
Implicit intents are a security risk because they don't specify a single recipient app. Instead, they broadcast data to any application that declares it can handle that type of intent. This means a malicious app with a matching intent filter can eavesdrop on sensitive communications, such as authentication tokens or personal data. The risk is amplified by two specific broadcast types: ordered broadcasts, where a high-priority malicious receiver can block or alter the data mid-chain, and sticky broadcasts, which persist data in the system long after the initial send, increasing the window for exposure. Furthermore, intents can grant temporary URI permissions, giving the receiver access to files or content the sender app protects. A malicious interceptor gains those same privileges, leading to unauthorized data access. Identifying and fixing every instance of this pattern in a large codebase is challenging. An ASPM platform like Plexicus can automatically detect these flaws via SAST, and its AI-powered remediation can suggest the specific code changes—like switching to explicit intents or protected broadcasts—saving significant manual review time.
Impact réel

Real-world CVEs caused by CWE-927

  • CVE-2022-4903

    An Android application does not use FLAG_IMMUTABLE when creating a PendingIntent.

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

  1. 1

    This application wants to create a user account in several trusted applications using one broadcast intent:

  2. 2

    This application assumes only the trusted applications will be listening for the action. A malicious application can register for this action and intercept the user's login information, as below:

  3. 3

    When a broadcast contains sensitive information, create an allowlist of applications that can receive the action using the application's manifest file, or programmatically send the intent to each individual intended receiver.

  4. 4

    This application interfaces with a web service that requires a separate user login. It creates a sticky intent, so that future trusted applications that also use the web service will know who the current user is:

  5. 5

    Sticky broadcasts can be read by any application at any time, and so should never contain sensitive information such as a username.

Exemple de code vulnérable

Vulnerable Java

This application wants to create a user account in several trusted applications using one broadcast intent:

Vulnérable Java 
Intent intent = new Intent();
  intent.setAction("com.example.CreateUser");
  intent.putExtra("Username", uname_string);
  intent.putExtra("Password", pw_string);
  sendBroadcast(intent);
Charge utile de l'attaquant

This application assumes only the trusted applications will be listening for the action. A malicious application can register for this action and intercept the user's login information, as below:

Charge utile de l'attaquant Java 
IntentFilter filter = new IntentFilter("com.example.CreateUser");
  MyReceiver receiver = new MyReceiver();
  registerReceiver(receiver, filter);
Exemple de code sécurisé

Secure pseudo

Sécurisé 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.
Liste de contrôle de prévention

How to prevent CWE-927

  • Implementation If the application only requires communication with its own components, then the destination is always known, and an explicit intent could be used.
Signaux de détection

How to detect CWE-927

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.)

Correction automatique Plexicus

Plexicus détecte automatiquement CWE-927 et ouvre une PR de correction en moins de 60 secondes.

Codex Remedium analyse chaque commit, identifie cette faiblesse précise et livre une pull request prête à être relue avec le correctif. Pas de tickets. Pas de transferts.

Obtenir une démo Essayer Plexicus gratuitement
Questions fréquentes

Frequently asked questions

Qu'est-ce que CWE-927 ?

This vulnerability occurs when an Android app uses an implicit intent to send sensitive data, allowing any other app on the device to potentially intercept and read that information.

Quelle est la gravité de CWE-927 ?

MITRE n'a pas publié de note de probabilité d'exploitation pour cette faiblesse. Traitez-la comme un impact moyen jusqu'à ce que votre modèle de menace prouve le contraire.

Quels langages ou plateformes sont affectés par CWE-927 ?

MITRE lists the following affected platforms: Mobile.

Comment puis-je prévenir CWE-927 ?

If the application only requires communication with its own components, then the destination is always known, and an explicit intent could be used.

Comment Plexicus détecte et corrige CWE-927 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-927 à chaque commit. Lorsqu'une correspondance est trouvée, notre agent Codex Remedium ouvre une PR de correction avec le code corrigé, les tests et un résumé d'une ligne pour le relecteur.

Où puis-je en savoir plus sur CWE-927 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/927.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-927

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Ressources

Further reading

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