In this paper, we study some messaging design
decisions which resulted in a set of vulnerabilities in the
Android operating system, and we demonstrate how a malware
application can be built to abuse these vulnerabilities. The
application presents itself as a regular SMS messaging
application and uses its basic permissions to send/receive short
messages. Since many operators worldwide provide services
that allow users to transfer credits/units through SMS, the
application abuses this service to transfer credits from users
illegally. The “permission” subsystem, the “broadcast
receiver” subsystem, and the message-sending mechanism
contribute to forming a haven for SMS malware by granting
them absolute control over sending, receiving, and hiding SMS
messages. Accordingly, the malicious application hides any
acknowledgments from the telecom operator that might
appear after a credit transfer transaction. This enables
malware to drain the balance of the attacked user and has the
potential to cause damage to a large number of users as well as
telecom operators. The application was demonstrated on a
local operator and it successfully passed standard screening
procedures that claim to catch malware. A set of possible
solutions are also presented in order to mitigate the risks of
such attacks