Building a Trusted
Ecosystem forMillions of Apps
The important role of App Store
protections
June 2021

2007“We’re trying to do two diametrically opposed things
at once: provide an advanced and open platform todevelopers while at the same time protect iPhone
users from viruses, malware, privacy attacks, etc.
This is no easy task.”
Steve Jobs, 2007¹

2016“Use the official application marketplace only. Users
should … not [download applications] from third-party
sources, to minimise the risk of installing a malicious
application. Users should not sideload applications if they
do not originate from a legitimate and authentic source.”
European Union Agency for Cybersecurity (ENISA), 2016²

2017“The best practices identified for mitigating threats fromvulnerable apps are relevant to malicious and privacyinvasive apps. Additionally, users should avoid (andenterprises should prohibit on their devices) sideloadingof apps and the use of unauthorized app stores.”
U.S. Department of Homeland Security Report, 2017³

Today, our phones are not just phones; they store some of our most sensitive
information about our personal and professional lives. We keep them with us
wherever we go, and we use them to call and text with loved ones, take and store
photos of our children, give us directions when we’re lost, count our steps, and sendmoney to friends. They are with us in happy times, and in times of emergencies.

Did you know?

Apple reviews all apps andupdates on the App Store
to intercept those that could
harm users. This includes
apps that contain inappropriate content, invade user
privacy, or contain known
malware, which is software
used for bad or dangerous
purposes.

A study found that devices
that run on Android had 15
times more infections frommalicious software thaniPhone, with a key reason
being that Android apps
“can be downloaded fromjust about anywhere,” while
everyday iPhone users canonly download apps from one
source: the App Store.4

We designed iPhone with this in mind. We built the App Store to give developersfrom around the globe a place to build innovative apps that can reach a growing andthriving global community of over a billion users. Nearly two million apps are available
for users to download on the App Store, with thousands of apps added every week.
Given the sheer scale of the App Store platform, ensuring iPhone security and safety
was of critical importance to us from the start. Security researchers agree that iPhoneis the safest, most secure mobile device, which allows our users to trust their devices
with their most sensitive data. We built industry-leading security protections into
the device, and we created the App Store, a trusted place where users can safely
discover and download apps. On the App Store, apps come from known developers
who have agreed to follow our guidelines, and are securely distributed to users
free from interference from third parties. We review every single app and each app
update to evaluate whether they meet our high standards. This process, which we areconstantly working to improve, is designed to protect our users by keeping malware,cybercriminals, and scammers out of the App Store. Apps designed for children must
follow strict guidelines around data collection and security designed to keep children
safe, and must be tightly integrated with iOS parental control features.
And when it comes to privacy, we don’t just believe it’s important – we believe
it is a fundamental human right. That principle guides the high privacy standards
we build into our products: we collect only the personal data strictly necessary todeliver a product or service, we put the user in control by asking them for permission
before apps can access sensitive data, and we provide clear indications when apps
access certain sensitive features like the microphone, camera, and the user’s location.
As part of our continued commitment to user privacy, two of our newest privacy
features – privacy labels on the App Store and App Tracking Transparency – give ourusers unprecedented control over their privacy, with increased transparency andinformation to help them make informed choices. Thanks to all these protections,users can download any app on the App Store with peace of mind. This peace of mind
also benefits developers, who are able to reach a wide audience of users who feel
confident downloading their apps.

3This approach to security and privacy has been highly effective. Today, it isextremely rare for any user to encounter malware on iPhone.5 Some have suggested
that we should create ways for developers to distribute their apps outside of the
App Store, through websites or third-party app stores, a process called “sideloading.”
Allowing sideloading would degrade the security of the iOS platform and expose users
to serious security risks not only on third-party app stores, but also on the App Store.
Because of the large size of the iPhone user base and the sensitive data stored on theirphones – photos, location data, health and financial information – allowing sideloading
would spur a flood of new investment into attacks on the platform. Malicious actors
would take advantage of the opportunity by devoting more resources to develop
sophisticated attacks targeting iOS users, thereby expanding the set of weaponized
exploits and attacks – often referred to as a “threat model” – that all users need to besafeguarded against. This increased risk of malware attacks puts all users at greaterrisk, even those who only download apps from the App Store. Additionally, even users
who prefer to only download apps from the App Store could be forced to download an
app they need for work or for school from third-party stores if it is not made available
on the App Store. Or they could be tricked into downloading apps from third-party app
stores masquerading as the App Store.
Studies show that third-party app stores for Android devices, where apps are notsubject to review, are much riskier and more likely to contain malware as opposed
to official app stores.6 As a result, security experts advise consumers against using
third-party app stores because they are unsafe.3,7 Allowing sideloading would open thedoor to a world where users may not have a choice but to accept these risks, becausesome apps may no longer be available on the App Store, and scammers could trickusers into thinking they are safely downloading apps from the App Store when that is
not the case. Sideloading would expose users to scammers who will exploit apps tomislead users, attack iPhone security features, and violate user privacy. It would also
make it more difficult for users to rely on Ask to Buy, a parental control feature thatallows parents to control their children’s app downloads and in-app purchases, andScreen Time, a feature to manage their and their children’s time with their devices.
Scammers would have the opportunity to trick and mislead kids and parents by
obfuscating the nature of their apps, making both features less effective.
In the end, users would have to constantly be on the lookout for scams, neverknowing who or what to trust, and as a result many users would download fewer
apps from fewer developers. Developers themselves would become more vulnerable
to threats from malicious actors who could offer infected developer tools that
contain and propagate malware. Developers would also be more vulnerable to piracy,
undermining their ability to get paid for their work.

4

Let’s look at how a family’s everyday experience using theiriPhone would be different with sideloading. We’ll follow the dayof John and his 7-year-old daughter, Emma, as they navigate
this more uncertain world.

Real-world attacks on
platforms that allow
sideloading

Android apps aimed at children
were discovered to be engaging
in data collection practices
that violated kids’ privacy.
These apps continue to thrive
and target Android users on
third-party app stores, eventhough they were removed
from the Google Play Store.8

$ $

BUY

Malicious actors have placed
inappropriate or obscene ads
on apps targeted at kids.9

A sideloaded game bypasses parental controls
Emma asks John if she can play a game that she heard about fromher friends at school. John looks for the game on the App Store,
but the developer has only made it available on third-party app
stores. This makes John uneasy, but he downloads it because
Emma really wants to try the game, and the third-party app store
claims the app is appropriate for children. Later, on their way to thepark, when Emma is playing the game in the backseat of the car,the app bombards her with links to outside websites and targeted
advertisements. John had added his credit card information to buy
Emma a starter pack when he downloaded the game, but he didn’t
realize that the Ask to Buy parental controls would not work withthis sideloaded app. While she is playing, Emma purchases many
extra turns and special items, not realizing that her dad had notactually approved those purchases. The app also has embedded
third-party trackers, which collect, analyze, and sell Emma’s data
to data brokers, even though the app is marketed for kids.

5Real-world attacks on
platforms that allow
sideloading

Sideloaded apps on Android
have been known to carry out“locker” ransomware attacks.
These malicious apps, if installed,
lock users out of their phone ortarget their photos, unless theyagree to pay a ransom.10,11

Android users have been tricked
into using insecure methods todownload fake versions of apps
like Netflix and Candy Crush.
These fake apps, either when
given access or by exploiting
platform vulnerabilities, canspy on Android users via themicrophone, take screen shots of
their devices, view location, text
messages and contacts, steal
users’ login credentials, and makechanges to users’ phones.12,13,14
Others have been used to stealbanking credentials and take overusers’ bank accounts.15,16,17,18

A recent ransomware scam
involves an Android app
masquerading as a COVID-19
contact tracing app. If installed,
it encrypts all personal
information, leaving an email
address to contact if the user
wants to rescue their data.19

One app found on third-party
Android app stores tricks users
by pretending to be a system
update. Once installed, theapp displays a “Searching for
update” notification, as it gets
access to and steals the user’s
personal data, such as messages,
contacts, and pictures.20,21

At the park, the copy-cat filter app John had
sideloaded threatens to delete all of his photos
unless he pays up
When John and Emma are at the park, John sees an ad for a selfie
filter app from a well-known app developer that looks like it would
be fun to use with Emma. The ad takes him to a page to download
the app that looks like the app developer’s page on the App Store,
so John thinks he is protected, and does not realize he is actually
downloading a copy-cat version of the app from a third-party app
store. Because John thinks the filter app came from a well-known,trusted developer, he grants it permission to access his photos. Oncethe app starts running, however, he realizes he’s made a mistake –the app threatens to delete all of the photos on his camera roll unlesshe enters his credit card information and pays a ransom. iPhone
on-device protections give John control over which apps are allowed
to access his photos, but in this case the sideloaded app tricked him
into granting access to his photos by posing as a selfie filter app.

6

Real-world attacks on
platforms that allow
sideloading

Research shows that pirated
apps published on third-party
app stores cost developers
billions in lost revenue per year.22

Pirated and otherwise illegitimate
apps are widespread on Android.
Such apps include gaming appsthat allow cheating (e.g., a pirated
version of Pokémon Go with theability to simulate one’s location),
apps modified to provide pirated
access to premium content orfeatures, and illegal gambling andadult-content apps.23,24,25

John unknowingly downloads a pirated app
from a third-party app store
John’s friend loves a fitness app she’s been using and she
sends him a referral for him to try it out. But the referral only
works if he downloads the app through a third-party app store,
not through the App Store. He downloads the app, signing up
for a monthly subscription. However, what neither of them hadrealized was that this app had been pirated. That means thatthe money he pays every month is not going to the developer
who designed and built the app, but rather, going to thescammers who stole the app. John believed he was doing theright thing – supporting the developer of this awesome fitness
app – but instead he was lining the pockets of scammers,
unknowingly supporting a fraudulent scheme that deprives
developers of their earnings.

7

Learn more about
Apple’s privacy
protections

To learn more about how the
App Tracking Transparency andprivacy labels on the App Store
give you control and transparency
on how apps collect and use yourdata, read A Day in the Life ofYour Data and visit apple.com/
privacy/control.

A sideloaded app violates John’s privacy
John heard about a new sleep tracking app that he’d like to try,
but it is not available on the App Store. He downloads it from athird-party app store, signs up using his email address, and starts
using it to monitor his sleep quality. The app claims that it keeps
its users’ health and usage data completely private, and does notlink it with outside data or share it with third parties. However,this claim turns out to be completely false. Because the app was
sideloaded, the app developer was free to do whatever theywanted, so the app tracked John using his email address without
asking for his permission. This allows the developer to link hisdata with information collected from other apps and sell his
health data to data brokers, without user permission and without
having to worry about being stopped.

8

iPhone is used every day by over a billion people – for banking, to manage health data, and to
take pictures of their families. This large user base would make an appealing and lucrative target
for cybercriminals and scammers, and allowing sideloading would spur a flood of new investment
into attacks on iPhone, well beyond the scale of attacks on other platforms like Mac. Scammers
would be galvanized to develop tools and expertise to attack iPhone device security. The App Storeis designed to detect and block today’s attacks, but changing the threat model would bypass these
protections. Scammers would then use their newly developed tools and expertise to target thirdparty stores as well as the App Store, which would put all users at greater risk, even those who only
download apps on the App Store. The additional distribution channels introduced by sideloading
provide malicious actors expanded opportunities to exploit system vulnerabilities, thereby
incentivizing attackers to develop and disseminate more malware.
This means that users like John, who had grown to take the safety and protection of iPhone
and the App Store for granted, would have to constantly be on the lookout for the ever-changing
tricks of cybercriminals and scammers, never knowing who or what to trust. In some cases,
John may have no choice but to take a risk by sideloading an app that is not available on the
App Store from a third-party store, or he may be tricked into doing so. In the most serious
cases, sideloaded apps pretending to be something they’re not – for example, claiming to
be an Apple software update or disguising their download page to look like the App Store– could attempt to break iPhone on-device protections to get access to protected data likemessages, photos, and location. In light of all these risks and scams, John would be a lot
more cautious about which apps to download. In the end, he would download fewer apps,
and stick to those from a few trusted developers, making it harder for new, smaller developers
to reach users with innovative new apps. He would not have the peace of mind that comeswith knowing that apps on his iPhone are the safest options for him and his daughter.

Did you know?
Users who are worried about their security and privacy are more likely to download fewer apps and todelete apps from their devices.26,27,28 A less secure ecosystem, in which users do not feel safe downloading
apps, could mean users are less likely to try out innovative new apps or take a chance on apps coming from new or
lesser-known developers. This could blunt the growth of the app economy, harming both users and developers.

9Apple’s security layers and App Review protect
John, Emma, and their devices

To protect iOS users from malicious apps and provide the world’s best platformsecurity, we take a multi-pronged approach, with many layers of protection. iOS
poses unique security challenges because users continuously and frequently
download new apps onto their devices, and because iOS devices need to be safeenough for children to use unsupervised. This means that we take a heightened
approach to security on iPhone compared to Mac, because the population of users,
as well as their behaviors and expectations, are different.
•

As on Mac, we use automated software to scan apps for known malware,preventing them from ever making it onto the App Store and thus everreaching or harming users.

•

Additionally, app developers are required to submit a description of their
app and its features. This information is reviewed by a team of experts for
accuracy during the App Review process, and is presented to users when
they evaluate whether to download an app. This process creates a high barrier
against the most common scams used to distribute malware: misrepresenting
the malware as a popular app, or claiming to offer enticing features that are notactually provided.

•

In addition to verifying whether the app’s features work as described andwhether the app’s App Store page is accurate, these experts also manuallycheck that the app doesn’t unnecessarily request access to sensitive dataand evaluate that apps targeted at children comply with stringent datacollection and safety rules.

•

In cases where an app makes it into the App Store but is later discovered
to violate our guidelines, we work with the developer to quickly resolve theissue. In dangerous cases, involving fraud and malicious activity, the app isimmediately removed from the App Store and users who downloaded the apps
can be notified of the app’s malicious behavior.

•

If a user has an issue with an app downloaded from the App Store,
Apple Care is available to provide support and issue refunds.

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The goal of App Review is to ensure that apps on the App Store are trustworthy
and that the information provided on an app’s App Store page accurately represents
how the app works and what data it will access. We are constantly improving thisprocess: we update and refine our tools and our methodology continuously.
Once users download an app through the App Store, they are able to control
how that app functions and what data it is able to access, using features suchas App Tracking Transparency and permissions. Parents can further control what
their kids buy with the Ask to Buy feature, how much time they spend on certain
categories of apps with Screen Time features, and what data they share. Users arealso able to centrally manage all app-related payments, and are able to easily viewand cancel subscriptions that are paid for via In-App Payments. These controls
could not be fully enforced on sideloaded apps.
In addition to the protections provided by App Review, we design our devices’
hardware and software to provide a last line of defense in case a harmful app isdownloaded on the device. For example, apps downloaded on iPhone from the App
Store are “sandboxed,” meaning they are not able to access files stored by otherapps or make changes to the device unless explicitly permitted by the user.
The best defense relies on a combination of all layers – robust App Review tohelp prevent the installation of malicious apps, and robust platform protections
to limit the damage malicious apps can inflict. The security designed into iOS
provides users with powerful protections that are the best of any consumer device,
but those protections are not engineered to protect against choices a user might
be tricked into making. App Review gives teeth to App Store policies designed toprotect users from apps that may attempt to harm them or trick them into granting
access to sensitive data. And, in the very serious instances of malicious apps trying
to bypass on-device protections, App Review makes it harder for them to get on
users’ devices in the first place.
The end result is that security experts agree iPhone is the safest, mostsecure mobile device. Apple’s many layers of security provide users with an
unparalleled level of protection from malicious software, giving users peaceof mind.

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App Review

Through the App Review process, we work to ensure apps come from vetted
sources and are free of known malicious components. We also check that theapps aren’t trying to trick you into making unwanted purchases or providing
access to personal data. We screen developers and users, expelling those who
misbehave. While App Review processes do not prevent the distribution of every
single low-quality app, we continue to innovate and improve its technology,
practices, and processes.
Apple’s app protections in action in 2020•

100,000 new apps and updates are reviewed every week on average by
a team of over 500 dedicated experts, who review apps in different languages.

•

Nearly one million problematic new apps and a similar number of updates
were rejected or removed:–More than 150,000 for being spam or copycats, or misleading users–

More than 215,000 for violating privacy guidelines–

More than 48,000 for containing hidden or undocumented features–

About 95,000 for fraudulent violations, predominantly for including “baitand switch” functionalities to commit criminal or other forbidden actions•

Apple stopped over $1.5 billion in potentially fraudulent transactions.

•Apple expelled 470,000 teams from the Apple Developer Program forfraud-related reasons. It also rejected nearly 205,000 developer enrollmentattempts over fraud concerns.

•

Apple deactivated 244 million customer accounts due to fraudulent
and abusive activity, including fake reviews. It also rejected 424 million
attempted account creations due to fraudulent and abusive patterns.

12App Review gives John peace of mind when hedownloads apps
The App Store security and privacy features give John peaceof mind when he downloads apps for himself and his daughter.
He knows that Apple screens 100% of apps on the App Storefor known malware, and that, compared to other devices, it isextremely rare for users to encounter malicious software on iPhone.

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Frequently Asked Questions

What is sideloading?

Learn more about
Apple’s protections“Sideloading” is the process of downloading and installing apps on a mobile
device from a source other than the official App Store, such as a website or
third-party app store. To protect user security and privacy, we designed iPhone
from the beginning not to allow sideloading for everyday users.

What is a threat model?
To learn more about how Apple
protects your security andprivacy on the App Store,
visit apple.com/app-store.

To learn more about how Apple
protects your location data,read the Location Services
White Paper.

To learn more about parental
control on iOS, visit apple.com/
families.

A threat model is the set of attacks and vulnerabilities that users need to besafeguarded against. Different devices, users, and environments have varying
threat models, and security needs to be built with this in mind. The App Store isa crucial component of protecting against the iPhone threat model. It is a trusted
place for users to securely download apps that are reviewed by Apple, fromknown developers who must abide by Apple’s guidelines.

Would allowing sideloading from websites and third-party app storeson iPhone threaten users who only download apps from the App Store?
Yes. By providing additional distribution channels, changing the threat model,
and widening the universe of potential attacks, sideloading on iPhone would put
all users at risk, even those who make a deliberate effort to protect themselves
by only downloading apps through the App Store. Allowing sideloading would
spur a flood of new investment into attacks on iPhone, incentivizing malicious
actors to develop tools and expertise to attack iPhone device security at an
unprecedented scale. Having developed expertise in ever more sophisticatedattacks, malicious actors would use it to target third-party stores as well as the
App Store, putting all users at greater risk. Additionally, even users who prefer
to only download apps from the App Store could be forced to download an app
they need for work or for school from third-party stores if it is not made available
on the App Store. Or they could be tricked into downloading apps from thirdparty app stores masquerading as the App Store.

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What is Apple’s App Review process?
We use a combination of sophisticated technology and human expertise tocarefully review every app and every update to evaluate whether they adhere
to the App Store’s strong guidelines on privacy, security, and safety. We relyon human expertise when automated review is not enough to detect specificissues, such as privacy violations or apps for children that do not adhere to
our strict guidelines. The guidelines have changed over time to respond to
new threats and challenges, with the goal of protecting users and providingthem with the very best experience on the App Store. 100,000 new apps andupdates are reviewed every week on average by a team of over 500 dedicatedexperts around the world.

What is being reviewed?
All apps and updates submitted to the App Store are subject to the App
Review process.

What parental controls are available on Apple devices?
We design features that allow parents to have control over how kids use
devices. Screen Time gives parents a better understanding of the time kids
spend using apps, visiting websites, and using devices. Screen Time also letsparents set the amount of time kids can spend each day on categories of apps
and websites. Additionally, Ask to Buy allows parents to approve or decline
kids’ app purchases and downloads right from their device. Ask to Buy has afifteen-minute timeout to prevent subsequent purchases.

What are App Tracking Transparency and privacy labels on the
App Store?
These new features provide users greater control over their data and theirprivacy. App Tracking Transparency requires apps to get the user’s permission
before tracking their data across apps or websites owned by other companies.
With privacy labels on the App Store, we require every app on the App Storeto give users an easy-to-view summary of the developer’s privacy practices,giving users key information about how an app uses their data.

15

Sources

1. Jobs, Steve, “Third Party Applications on the
iPhone,” October 17, 2007, accessed via
tidbits.com/2007/10/17/steve-jobss-iphone-sdkletter/.
2. ENISA, “Vulnerabilities - Separating Reality from
Hype,” European Union Agency for Cybersecurity,
August 24, 2016.
3. Griffin, Robert Jr., “Study on Mobile Device
Security,” U.S. Department of Homeland Security,
April 2017.

15. Palmer, Danny, “This Android trojan malware isusing fake apps to infect smartphones, steal bankdetails,” ZDNet, June 1, 2021.
16. O’Donnell, Lindsey, “Banking.BR Android Trojan
Emerges in Credential-Stealing Attacks,” ThreatPost,
April 21, 2020.
17. Stefanko, Lukas, “Android Trojan steals
money from PayPal accounts even with 2FA on,”WeLiveSecurity by ESET, December 11, 2018.

4. Nokia, “Threat Intelligence Report 2020,” Nokia,
2020.

18. Cybereason Nocturnus Team, “FakeSpy
Masquerades as Postal Service Apps Around theWorld,” Cybereason, July 1, 2020.

5. Johnson, Dave, “Can iPhones get viruses? Here’s
what you need to know,” Business Insider, March 4,
2019.

19. Stefanko, Lukas, “New ransomware posing as
COVID‑19 tracing app targets Canada; ESET offers
decryptor,” WeLiveSecurity by ESET, June 24, 2020.

6. Symantec, “Internet Security Threat Report,
Volume 23,” April 2018.

20. Yaswant, Aazim, “New Advanced Android
Malware Posing as ‘System Update’,” Zimperium,
March 26, 2021.

7. Golovin, Igor, “Malware in Minecraft mods: story
continues,” Kaspersky, June 9, 2021.
8. Lunden, Ingrid, “Google removes 3 Android
apps for children, with 20M+ downloads between
them, over data collection violations,” Tech Crunch,
October 23, 2020.
9. Henry, Josh, “Malicious Apps: For Play or Prey?”
United States Cybersecurity Magazine, 2021.
10. Schwartz, Jaime-Heather, “How to protect yourAndroid phone from ransomware – plus a guide toremoving it,” Avira, August 13, 2020.
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Photos, Videos on Android Devices,” ThreatPost,
June 24, 2020.
12. Owaida, Amer, “Beware Android trojan posing as
Clubhouse app,” WeLiveSecurity by ESET, March 18,2021.
13. Desai, Shivang, “SpyNote RAT posing as Netflix
app,” Zscaler, January 23, 2017.
14. Peterson, Andrea, “Beware: New Android
malware is ‘nearly impossible’ to remove,” The
Washington Post, November 6, 2015.

21. Aamir, Humza, “Beware of this newly discovered
Android spyware that pretends to be a system
update,” TechSpot, March 29, 2021.
22. Koetsier, John, “The Mobile Economy Has A$17.5B Leak: App Piracy,” Forbes, February 2, 2018.
23. Koetsier, John, “App Developers Losing $3-4
Billion Annually Thanks To 14 Billion Pirated Apps,”
Forbes, July 24, 2017.
24. Maxwell, Andy, “Cheat Maker Agrees to Pay
Pokémon Go Creator $5m to Settle Copyright
Infringement Lawsuit,” TorrentFreak, January 8,
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25. Campaign for a Commercial-Free Childhood,“Apps which Google rates as safe for kids violate theirprivacy and expose them to other harms,” December
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