An adversary examines screenshot images created by iOS in an attempt to obtain sensitive information. These images are used by iOS to aid in the visual transition between open applications and improve the user's experience with a device. An application can be at risk even if it properly protects sensitive information when at rest. If the application displays sensitive information on the screen, then the potential exists for iOS to unintentionally record that information in an image file. An adversary can retrieve these images either by gaining access to the image files, or by physically obtaining the device and leveraging the multitasking switcher interface.
The table below shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf and ParentOf, and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as CanFollow, PeerOf, and CanAlsoBe are defined to show similar attack patterns that the user may want to explore.
Standard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.
This type of an attack requires physical access to a device to either excavate the image files (potentially by leveraging a Jailbreak) or view the screenshots through the multitasking switcher (by double tapping the home button on the device).
To mitigate this type of an attack, an application that may display sensitive information should clear the screen contents before a screenshot is taken. This can be accomplished by setting the key window's hidden property to YES. This code to hide the contents should be placed in both the applicationWillResignActive() and applicationDidEnterBackground() methods.
[REF-426] Jonathan Zdziarksi. "Hacking and Securing iOS Applications". Chapter 11 : Page 285 : Application Screenshots. First Edition. O'Reilly Media, Inc.. 2012.