Improper Export of Android Application Components

Opis

The Android application exports a component for use by other applications, but does not properly restrict which applications can launch the component or access the data it contains.

The attacks and consequences of improperly exporting a component may depend on the exported component:

- If access to an exported Activity is not restricted, any application will be able to launch the activity. This may allow a malicious application to gain access to sensitive information, modify the internal state of the application, or trick a user into interacting with the victim application while believing they are still interacting with the malicious application.

- If access to an exported Service is not restricted, any application may start and bind to the Service. Depending on the exposed functionality, this may allow a malicious application to perform unauthorized actions, gain access to sensitive information, or corrupt the internal state of the application.

- If access to a Content Provider is not restricted to only the expected applications, then malicious applications might be able to access the sensitive data. Note that in Android before 4.2, the Content Provider is automatically exported unless it has been explicitly declared as NOT exported.

Skutki

• Availability, Integrity

  Unexpected State; DoS: Crash, Exit, or Restart; DoS: Instability; Varies by Context

  Other applications, possibly untrusted, can launch the Activity.

• Availability, Integrity

  Unexpected State; Gain Privileges or Assume Identity; DoS: Crash, Exit, or Restart; DoS: Instability; Varies by Context

  Other applications, possibly untrusted, can bind to the Service.

• Confidentiality, Integrity

  Read Application Data; Modify Application Data

  Other applications, possibly untrusted, can read or modify the data that is offered by the Content Provider.

Zapobieganie

• Build and Compilation · Attack Surface Reduction

  If they do not need to be shared by other applications, explicitly mark components with android:exported="false" in the application manifest.

• Build and Compilation · Attack Surface Reduction

  If you only intend to use exported components between related apps under your control, use android:protectionLevel="signature" in the xml manifest to restrict access to applications signed by you.

• Build and Compilation, Architecture and Design · Attack Surface Reduction

  Limit Content Provider permissions (read/write) as appropriate.

• Build and Compilation, Architecture and Design · Separation of Privilege

  Limit Content Provider permissions (read/write) as appropriate.

Słabość nadrzędna

• CWE-285 Improper Authorization

Kiedy powstaje

• Architecture and Design

Dotyczy

Not Language-Specific, Mobile

Źródła

1. Security Tips — Android Open Source Project, 2013