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PIM

Precise Intent Matcher

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PIM

PIM

The Precise Intent Matcher (PIM) can be used as an alternative or a replacement for the CONNECT operator of the AQL. It connects Intent-Sinks with Intent-Sources and thereby detects ICC and IAC flows between one or more apps. To do so, it builds up a client-server connection with an Android device or emulator. Through this connection PIM request the construction of Intents and Intent-Filters based on the provided input (Intent-Sinks & -Sources). Whenever the Android system installed on the device or emulator decides, that an Intent’s action-category-data triple matches the one of an Intent-Filter, a connection between the associated Intent-Sink and -Source is derived. Accordingly PIM takes multiple AQL-Answers as input and outputs a single one.

Example

The goal of the following query, for example, is to find any flows inside and between A and B.

MATCH [
	Flows IN App(’A.apk’) ?,
	IntentSources IN App(’A.apk’) ?,
	IntentSinks IN App(’A.apk’) ?,
	Flows IN App(’B.apk’) ?,
	IntentSources IN App(’B.apk’) ?,
	IntentSinks IN App(’B.apk’) ?
]

The MATCH operator refers to PIM. The questions in its scope may be answered by different tools such as FlowDroid or IC3. A complete and fully described example can be found in the referenced paper (see Publications).

Configuration and Launch Parameters

When PIM is executed for the first time, you are asked to setup PIM unless you have defined the following parameters in the config.properties file beforehand:

Entry Meaning
sdkPath=/path/to/Android/Android/sdk Path to the Android SDK. The Android development bridge located in this directory will be called.
deviceName=emulatorToBeUsed Specify the name of the emulator or device you want to execute PIM on.
rebootAllowed=false Determines if PIM has the permission to restart the selected device.
appRelocationPath=/search/path Provide a directory where the analyzed apps may be found. For example, the upload directory of an AQL-WebService.

The following launch parameters can be provided while running PIM:

Parameter Meaning
start Starts the selected emulator or device and the PIM-Server on it.
stop Stops the selected emulator or device.
ask %ANSWER% [, %ANSWER%]* All provided AQL-Answers (%ANSWER%) will be matched by PIM. At least one answer must be specified. (If the PIM-Server is not started, it will be started and stopped once the execution finishes.)

PIM together with IC3

IC3 can be used to get information about IntentSinks and IntentSources. PIM is able to accurately connect these to inter-component flows. To fully use this feature, PIM’s underlying AQL-System should be setup (Tutorial: Configuration). It should be setup to use a taint analysis tool such as FlowDroid. This tool should be ran with the sources and sinks in the following file SourcesAndSinks_intent.txt. This is required to find additional IntentSources that share the same action-category-data triples as those found by IC3. The AQL-System’s configuration should look similar to the following one and be stored in PIM’s root directory under the name windows.xml or linux.xml (depending on your operating system):

<config>
	<tools>
		<tool name="FlowDroid" version="X" external="false">
			<priority>1</priority>
			<execute>
				<run>/path/to/FlowDroid/script.sh/.bat that uses SourcesAndSinks_intent.txt</run>
				<result>/path/to/FlowDroid/results/%APP_APK_FILENAME%_result.txt</result>
				<instances>0</instances>
				<memoryPerInstance>8</memoryPerInstance>
			</execute>
			<path>/path/to/FlowDroid</path>
			<questions>IntraAppFlows</questions>
		</tool>
	</tools>
</config>

Publications

License

PIM is licensed under the GNU General Public License v3 (see LICENSE).

Contact

Felix Pauck (FoelliX)
Paderborn University
fpauck@mail.uni-paderborn.de
http://www.FelixPauck.de