CWE-925

Variant Abstraction Level
Pillar — Highest-level weakness category
Class — Abstract, language-independent
Base — Specific enough to detect
Variant — Tied to specific technology
Compound — Requires multiple weaknesses Incomplete MITRE CWE Status
Stable — Fully reviewed and complete
Draft — Under development, may change
Incomplete — Partially defined by MITRE
Deprecated — No longer recommended
Obsolete — Replaced by another CWE
Improper Verification of Intent by Broadcast Receiver

Description

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

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.

Consequences

Integrity — Gain Privileges or Assume Identity

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

Mitigations

Phase: Architecture and Design

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

Detection

Automated Static Analysis

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.)