Input Prompt - T1411 (3dd58c80-4c2e-458c-9503-1b2cd273c4d2)
The operating system and installed applications often have legitimate needs to prompt the user for sensitive information such as account credentials, bank account information, or Personally Identifiable Information (PII). Adversaries may mimic this functionality to prompt users for sensitive information.
Compared to traditional PCs, the constrained display size of mobile devices may impair the ability to provide users with contextual information, making users more susceptible to this technique’s use.(Citation: Felt-PhishingOnMobileDevices)
Specific approaches to this technique include:
Impersonate the identity of a legitimate application
A malicious application could impersonate the identity of a legitimate application (e.g. use the same application name and/or icon) and get installed on the device. The malicious app could then prompt the user for sensitive information.(Citation: eset-finance)
Display a prompt on top of a running legitimate application
A malicious application could display a prompt on top of a running legitimate application to trick users into entering sensitive information into the malicious application rather than the legitimate application. Typically, the malicious application would need to know when the targeted application (and individual activity within the targeted application) is running in the foreground, so that the malicious application knows when to display its prompt. Android 5.0 and 5.1.1, respectively, increased the difficulty of determining the current foreground application through modifications to the ActivityManager API.(Citation: Android-getRunningTasks)(Citation: StackOverflow-getRunningAppProcesses). A malicious application can still abuse Android’s accessibility features to determine which application is currently in the foreground.(Citation: ThreatFabric Cerberus) Approaches to display a prompt include:
- A malicious application could start a new activity on top of a running legitimate application.(Citation: Felt-PhishingOnMobileDevices)(Citation: Hassell-ExploitingAndroid) Android 10 places new restrictions on the ability for an application to start a new activity on top of another application, which may make it more difficult for adversaries to utilize this technique.(Citation: Android Background)
- A malicious application could create an application overlay window on top of a running legitimate application. Applications must hold the
SYSTEM_ALERT_WINDOWpermission to create overlay windows. This permission is handled differently than typical Android permissions, and at least under certain conditions is automatically granted to applications installed from the Google Play Store.(Citation: Cloak and Dagger)(Citation: NowSecure Android Overlay)(Citation: Skycure-Accessibility) TheSYSTEM_ALERT_WINDOWpermission and its associated ability to create application overlay windows are expected to be deprecated in a future release of Android in favor of a new API.(Citation: XDA Bubbles)
Fake device notifications
A malicious application could send fake device notifications to the user. Clicking on the device notification could trigger the malicious application to display an input prompt.(Citation: Group IB Gustuff Mar 2019)