According to WikiLeaks, HighRise is an Android application designed for mobile devices running Android 4.0 to 4.3. It provides a redirector function for SMS messaging that could be used by a number of IOC tools that use SMS messages for communication.
WikiLeaks claims this can be used by the CIA to communicate between implants and listening posts.
HighRise acts as a SMS proxy that provides greater separation between devices in the field ("targets") and the listening post (LP) by proxying "incoming" and "outgoing" SMS messages to an internet LP. Highrise provides a communications channel between the HighRise field operator and the LP with a TLS/SSL secured internet communication. - says WikiLeaks