Apple explains security & privacy risks of side-loading in detailed new paper

Apple has published a new research paper taking a deep dive into some of the security and privacy risks of side-loading, or obtaining apps outside of the App Store.

The whitepaper, "Building a Trust Ecosystem for Millions of Apps," is an update on a previous version released in June. It leaves behind the approach of using fictional characters to explain security threats in favor of a more academic tone.

From the start, the paper takes a hard stance against side-loading, claiming that the practice would "cripple the privacy and security protections that have made iPhone so secure, and expose users to serious security risks."

Apple says that being forced to allow side-loading on iOS would allow harmful apps to proliferate among users, take away user control once apps are already downloaded onto their systems, and mandate removing protections from sensitive areas on an iPhone. The company claims these risks would be present even if side-loading was only available through third-party app stores on a device.

"Users could be forced to sideload an app they need for work or school," Apple writes. "Users also may have no choice other than sideloading an app that they need to connect with family and friends because the app is not made available on the

App Store."

The rest of the paper takes a deep dive into the current mobile threat landscape, using statistics and examples of current spyware that leverage side-loading or tricking users to spread.

Apple gives specific malware examples too, including adware HiddenAds, ransomware CryCryptor, and surveillance app FakeSpy. Notably, those mobile threats are all present on Android, which Apple used as an example of the dangers of allowing side-loading.

The Cupertino tech giant highlights research suggesting that the iPhone is the most secure mobile consumer device. It also details some of the methods that make malware rare on the platform, including the App Review process and an iPhone's built-in layers of protection.

Forcing Apple to support sideloading on iOS through direct downloads or third-party app stores would weaken these layers of security and expose all users to new and serious security risks: It would allow harmful and illegitimate apps to reach users more easily; it would undermine the features that give users control over legitimate apps they download; and it would undermine iPhone on-device protections. Sideloading would be a step backwards for user security and privacy. Supporting sideloading on iOS devices would essentially turn them into "pocket PCs," returning to the days of virus-riddled PCs.

The research paper comes in response to increasing talk of side-loading as a potential remedy for antitrust concerns. Both the U.S. and European Union, for example, are exploring legislation or rules that could force Apple to allow side-loading on its platforms.

Apple has argued against wide adoption of side-loading in the past, including in court during the Epic Games v. Apple trial. Company CEO Tim Cook also spoke out against the practice in the EU earlier in 2021, claiming that it would threaten iPhone security.

Individual users can side-load through Xcode now, but it requires a modicum of technical ability to do so. Enterprise certificates exist as well, but there are restrictions on what it can be used for, what volumes of installs are allowed, and more.

While Android can be configured to allow side-loading, it is not shipped with the feature enabled by default. Both Google and Samsung consider it a security risk.

Compared to previous iterations of its security research, the new white paper is much more in-depth and features expanded information on what it believes are the threats of side-loading. The paper is available to download.

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17 Comments

amar99 180 comments · 14 Years

About 3 years ago

Apple, next please explain the security and privacy risks of allowing a backdoor into people's devices, no matter what form that takes. Thanks.

mobird 758 comments · 20 Years

Who determines whether an app is "legitimate or illegitimate" and what is considered "legitimate"?

lkrupp 10521 comments · 19 Years

Kinda rings hollow when the Apple II and the Mac have allowed ‘side-loading’ since day one. I think I have come over to the side of those wanting to ‘side-load’. As for those who could be compromised by installing software, make it like the Mac and Gatekeeper. You can install whatever you want but if the software is not signed and verified you need to jump through some hoops to screw yourself. And if you screw yourself, have your bank account emptied, and lose all your personal data, well then, that’s totally on you. And I agree with the idea that the vast majority of iOS users will stick with the App Store. I know I will.

Secondly, we read all the articles about how leaky Android is regarding security but we don’t see reports of massive compromises of Android user’s. I know a lot of people who use Android phones and not one of them has lamented having their data stolen. Are they more careful than iOS users?

Apple has used the security and privacy issue as one of the pillars of its marketing campaigns. It’s a pillar that’s a little unstable these days.

libertymatters 44 comments · 3 Years

'Side loading' also known, prior to 2007, as installing an application on your computer. The key phrase here being 'your computer'. Who does Apple think they are to deny people the right to install any application they want on THEIR iPhone? Apple's entire case falls apart when you realize the Macintosh can still 'side load' applications to this day. Right-click, open. Annoyed by that? Disable Gatekeeper completely with a command in the Terminal. Why does this 'side loading' persist on the Macintosh? Simple, their customers would not tolerate such computer tyranny. Remember, Gatekeeper was added in to the Macintosh in Snow Leopard. iPhone customers should start to speak up about Apple's heavy handedness on their iPhones. The iPhone's walled garden should be optional just like it is on the Macintosh. Heck, most times I'd choose to stay in the walled garden for security, but when Apple gets heavy handed, like they are today with their outrageous censorship on the App Store and Podcasts, we need an opt out.

Bottom-line, this is about maintaining 30% profit on apps and control of people's devices. It is as simple as that.

rcfa 1123 comments · 17 Years

Apple can’t have it both ways:

1) For legitimate reasons they want to control what apps are associated with an Apple branded AppStore, as they affect the Apple brand.

OK, so then, since Apple has no right to act as a private industry censorship authority, they must allow users to install what Apple considered unsavory apps some other way on the devices the bought and own.

OR

2) Apple wants to control privacy and security, then it must allow for more fine-grained access to resources (e.g. access to MAC addresses if the user confirms and the app can demonstrate a legitimate use during the application process) and permit all apps to be listed in their AppStore.

Also, there are some restrictions, like the ban on emulators, which in the context of sandboxed apps makes no sense. If someone ports e.g. Previous to iPadOS allowing legacy NeXT apps to run within a sandboxed emulator, exactly what are privacy implications supposed to be?

As it stands, sideloading aka installing apps, should always be possible; Apple can warn against the potential risks, but the decision must remain the users’.

I’m glad Apple doesn’t manufacture cutlery: it would be spoons only, because knives are dangerously sharp, and forks and chopsticks might get someone’s eyes poked…