Weakness · High
CWE-926: Improper Export of Android Application Components
What it is
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.
- Severity (our rating)
- High
- Likelihood of exploit
- Not rated by MITRE
- Introduced during
- Architecture and Design
- Exploited in the wild
- No CVE in CISA's catalog
In more detail
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.
What an attacker can do
- Unexpected State (Availability, Integrity)
- DoS: Crash, Exit, or Restart (Availability, Integrity)
- DoS: Instability (Availability, Integrity)
- Varies by Context (Availability, Integrity)
- Gain Privileges or Assume Identity (Availability, Integrity)
- Read Application Data (Confidentiality, Integrity)
- Modify Application Data (Confidentiality, Integrity)
How to prevent it
Build and Compilation
- If they do not need to be shared by other applications, explicitly mark components with android:exported="false" in the application manifest.
- 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.
- Limit Content Provider permissions (read/write) as appropriate.
- Limit Content Provider permissions (read/write) as appropriate.
How to find it
- Automated Static Analysis. 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.)
H2 Security
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