android-intent-security

This skill provides guidelines and patterns to secure Android components (Activities, Services, Broadcast Receivers, Content Providers) and handle Intents safely, preventing privilege escalation and unauthorized access.

Glossary

• Intent: An asynchronous messaging object used to request an action from another app component.
• Exported component: A component (android:exported="true") that can be launched by other apps on the device.
• Sticky intent: A broadcast intent that remains in the system cache after it's sent, allowing any app to retrieve its contents.
• Signature permission: A permission whose protection level is set to signature, granted only to apps signed with the same developer key.
• onNewIntent: An activity lifecycle callback invoked when an activity is launched with FLAG_ACTIVITY_SINGLE_TOP and is already running at the top of the history stack.
• PendingIntent: A token granted to a foreign application (for example, system services) allowing it to execute a predefined Intent with the creator's permissions.
• Mutable PendingIntent: A PendingIntent whose underlying Intent parameters can be modified by the receiving application.
• ContentProvider: A component that encapsulates data and provides it to other applications via standard query/insert interfaces.
• IntentSanitizer: A utility class in AndroidX Core used to build a safe, sanitized copy of an incoming Intent by filtering out unauthorized components, actions, or extras.
• Intent redirection (forwarding): A vulnerability where an application receives an intent from an untrusted source and uses it to launch a private, non-exported component.

Prerequisites

• The agent MUST be able to describe the function and security implications of onCreate, onNewIntent, and the singleTop launch mode.
• The agent MUST be able to declare <activity>, <service>, <receiver>, and <provider> tags in AndroidManifest.xml and define their android:exported and android:permission attributes.
• The agent MUST be able to implement signature verification checks using PackageManager.