COMMON WEAKNESS ENUMERATIONIncomplete

CWE-925

Improper Verification of Intent by Broadcast Receiver

The Android application uses a Broadcast Receiver that receives an Intent but does not properly verify that the Intent came from an authorized source.

Abstraction

Variant

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

The Android application uses a Broadcast Receiver that receives an Intent but does not properly verify that the Intent came from an authorized source.

Extended description

Certain types of Intents, identified by action string, can only be broadcast by the operating system itself, not by third-party applications. However, when an application registers to receive these implicit system intents, it is also registered to receive any explicit intents. While a malicious application cannot send an implicit system intent, it can send an explicit intent to the target application, which may assume that any received intent is a valid implicit system intent and not an explicit intent from another application. This may lead to unintended behavior.

Terminology

Alternate terms and usages

Intent Spoofing

Root cause

How and when does the problem arise?

Lifecycle phase

Architecture and Design

Risk

What does successful exploitation lead to?

Gain Privileges or Assume Identity

Affected security scopes: Integrity

Another application can impersonate the operating system and cause the software to perform an unintended action.

Defence

How is it prevented and fixed?

Architecture and Design

Architecture and design approach

Detail
Before acting on the Intent, check the Intent Action to make sure it matches the expected System action.

Verification

How is it detected?

Automated Static Analysis

High
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)