Mobile devices and applications are no longer an accessory – they’re central to our daily lives. Gartner predicts the number of mobile apps downloaded will double to 45 billion this year – and they’re only getting smarter. Today’s apps are increasingly essential to accessing critical business applications, connecting with friends on the go and even adopting digital wallets.
While these apps make our lives easier, they also give a wider group of application developers and advertising networks the ability to collect information about our activities and leverage the functionality of our devices.
At the same time the companies, consumers and government employees who install these apps often do not understand with who and how they are sharing personal information. Even though a list of permissions is presented when installing an app, most people don’t understand what they are agreeing to or have the proper information needed to make educated decisions about which apps to trust.
More concerning is that many apps collect information or require permissions unnecessary for the described functionality of the app. This is not the first time this issue has surfaced – reports of popular apps collecting irrelevant information or transmitting data when devices are turned off has led to significant backlash. However, less is known about the state of privacy across the entire application ecosystem.
To get a sense of the state of application privacy today, my company’s Mobile Threat Center (MTC) analyzed over 1.7 million apps on the Google Play market from March 2011 to September 2012.
We found a significant number of applications contain permissions and capabilities that could expose sensitive data or access device functionality that it might not need. We also determined these apps had permission to access the Internet, which could provide a means for exposed data to be transmitted from the device.
Of particular interest, free applications were much more likely to access personal information than paid applications. Specifically, free apps are 401 percent more likely to track location and 314 percent more likely to access user address books than their paid counterparts.
- 24.14 percent of free apps have permission to track location, while only 6.01 percent of paid apps have this ability
- 6.72 percent of free apps have permission to access to your address book, while 2.14 percent of paid apps do
- 2.64 percent of free apps have permission to silently send text messages, whereas 1.45 percent of paid apps can
- 6.39 percent of free apps have permission to clandestinely initiate calls in the background, while only 1.88 percent of paid apps can
- 5.53 percent of free apps have permission to access the device camera, whereas only 2.11 percent of paid apps have this access.
When looking at the disparity between free versus paid apps, there is a common industry assumption that free apps collect information in order to serve ads from third-party ad networks. While this is true in some cases, we examined 683,238 application manifests and found the percentage of apps with the top five ad networks is much less than the total number tracking location (24.14 percent).
- 0.75 percent of apps feature AdMob ads
- 4.10 percent of apps feature ads from the AirPush network
- 1.51 percent of apps include Millennial Media ads
- 0.32 percent of apps include these ads from AdWhirl
- 2.34 percent of apps feature adds from the Leadbolt ad network.
This leads me to believe there are several apps collecting information for reasons less apparent than advertising.
Potential for misuse of permissions
Possibly more concerning are the other permissions being requested from applications like the ability to clandestinely initiate outgoing calls, send SMS messages and use a device camera.
An application that can clandestinely initiate a phone call could be used to silently listen to ambient conversations within hearing distance of a mobile device. Similarly, access to the device camera could enable a third party to obtain video and pictures of the area where the device is present, as was recently presented with the proof-of-concept Spyware PlaceRaider.
Silently sending SMS messages can also be a means to create a covert channel for siphoning sensitive information from a device. Further, the potential for stealth SMS messages or calls can have monetary repercussions by communicating with services that will subsequently charge a fee, such as calling a 1-900 in the U.S. or sending premium SMS messages.
Apps categories of most concern
The MTC also looked at different categories of applications and found some that seemed to be comparatively overstepping the needs of the applications when accessing certain permissions. For these apps, we cross-referenced the permissions requested with the functionality in the description of the apps. Our analysis noted apps that had the ability to do well more than a user could know and collect information not documented as necessary for the app to perform its intended use.
Cards & casino
Cards and Casino games include applications focused on imitating popular casino games for fun. In this category:
- 94 percent of free apps in this category that have permission to make outbound calls do not describe why the app would justifiably use this capability
- 83.88 percent of free apps that have permission to use the camera do so without any description of how the camera is being used by the app
- 84.51 percent of free apps that have permission to send SMS messages do so without any description of why the application would need to send SMS messages.
Racing Games are by far the most concerning category with an abnormally high number of apps removed from the marketplace over the time period of our analysis. Applications can be removed for a variety of reasons, including Google doing so for concerns over malware, questionable developers temporarily placing apps to phish for data, or for legitimate reasons, whereby an application is simply no longer being offered by a developer. During the manual portion of the research, this category contained the highest number of applications that the MTC would consider to be newly discovered malware.
- 99 percent of paid apps and 92.42 percent of free apps in this category have permission to send SMS messages and did not provide an explanation of why this capability would be necessary in the game
- 50 percent of free apps that have permission to use the camera do so without any description of how or why this capability is being used
- 94.54 percent of free apps with the ability of initiating outgoing calls did so without providing any description or justification on why this capability is necessary.
Upon further review
Our research also led to some unexpected insights as to the legitimate use of permissions. We examined cases where permissions or data collection was justified even though the reasons were not immediately obvious. We did this by installing apps to fully understand their functionality, as well as contacting several developers.
- There were a number of Cards and Casino apps from a specific developer that had the ability to use the device camera functionality. In reading the app descriptions and installing the application, there did not appear to be any reason for this capability. We contacted the developer who explained that with the premium version of the app, an icon would appear in the Tool Bar to enable the user to take a picture to use as a background for the game. This is a legitimate logical use that was not clearly communicated upfront for a consumer to understand or appreciate.
- During our initial analysis of outgoing call permissions, it seemed concerning that 12.51 percent of free Finance apps had the ability to initiate a phone call without going through the dialer interface and that 63.19 percent didn’t provide a description of this capability within the app. However, after installing a number of these applications, it became clear that this capability was legitimately used by users to contact local financial institutions.
The MTC’s analysis of the Google Play market shows the pervasiveness of mobile tracking and where apps could do a better job of disclosing why they need information up front and highlight functionality as a genuine user benefit. Our hope is that this research can give a better understanding of the current state of application privacy and provide insight to ensure the best actionable information is available to understand the effects on user privacy and the protection of enterprise data. We have several suggestions that the industry should consider:
- Correlate permissions to actual app functionality: Simply saying an app has the permission to track location, read contacts or silently perform an outgoing call doesn’t provide the necessary context of why this functionality is necessary for a specific app. Providing a means to communicate how permissions align with how the app works would help address this item.
- Better differentiate between permissions: There is a big difference between a Spyware app clandestinely placing an outgoing call to listen to ambient conversations within hearing distance of the device, and a financial app that provides the convenience of calling local branches from within an application. The manner in which permissions are currently presented does not provide a means for users to differentiate between the two. More needs to be done to provide developers with differentiated permissions and to perform the very different actions.
- Accept some exposure with free apps: It seems there is no such thing as a free lunch in mobile. If people choose to use free applications, they will likely need to provide information in exchange. Often times, the value provided by the app is well worth the information given up by a user; however, many do not realize that this tracking is happening and may not be making informed choices. Communicating why information is needed in a concise and easy-to-understand means could help people become more comfortable with sharing.
- A smaller amount of actionable data is beneficial: Helping people understand what is actually occurring on their device and with their data has considerably more value than a list of permissions. More educated users means they are more comfortable installing apps and less likely to uninstall once they see the number of permissions being requested without explanation.
The research contained in this report was conducted on the Android market. Apple does not disclose related information about its apps, and questions regarding the Apple App Store and related privacy statistics should be directed towards Apple.
This research was conducted via four primary means:
- Statistical analysis of application meta-data to determine permissions being requested by paid and free apps in various application categories
- Analysis of application descriptions to determine if the reasoning behind permission usage is being explained and justified by application features and functionality
- Statistical analysis of application manifests to correlate permissions being requested to AdNet usage
- Manual installation and research of applications to further explore key findings and to verify study methodology.