The Trouble With Fighting Your Users

Companies like Apple that try to control devices purchased by end-users create their own serious security problems. It turns out that Apple trying to protect itself from you makes you vulnerable to attackers.

Apple doesn’t want you to run anything on your phone that they didn’t approve. But of course, customers want to run whatever they want on the phone they bought, regardless of if Apple likes it. This creates end-user demand for jailbreaks — software that attacks their phone’s OS to remove Apple’s restrictions. Whenever one is discovered, Apple patches it, but another one is always discovered soon afterwards.

Right now, there’s a website,, that offers the easiest, most convenient jailbreak yet. You browse to the site on your iPhone, iPad, or iPod Touch, and suddenly it’s jailbroken and the non-Apple application stores like Cydia are available. It’s very slick, and much easier than any previous jailbreak, many of which required modifying OS images, caching key signatures from Apple, and other tasks that required at least some moderate technical savvy. People really like — it makes taking ownership of your own phone quick and easy!

How does it work? Well, it’s a combination of two exploits. When you visit the site, it loads a PDF that exploits a bug in Apple’s font rendering (iPhones render PDFs themselves, using Apple code — Adobe’s reader is not even involved) to load and run arbitrary code. Then that code exploits another vulnerability, in the iOS kernel, to run code as root, outside the app sandbox. This third piece of code jailbreaks the phone and installs the necessary backdoors to wrest control away from Apple and give it to the user.

But… there’s a problem here. The fact that this works means that there’s an unpatched remote root exploit on every iOS device. That is, on an iPhone, iPad, or iPod Touch, any website you visit or any email you receive can silently load and run arbitrary code on your device, which will then reside there permanently and do whatever the attacker wants. How do you know this hasn’t already happened to your phone, and your location isn’t being tracked, your calls tapped, your SMS messages and web passwords forwarded to some Russian crime syndicate? You don’t. There’s no way to know, because there’s no anti-malware software for iOS — Apple would never approve it anyway, since you’re not “supposed” to be able to run anything but Apple-approved apps anyway.

In a normal, open ecosystem, like that on PCs, this problem would be less likely to happen. If a security researcher discovered remote exploits like this, they would often follow responsible disclosure practices, and contact the vendor and let them know about the problem so it could be fixed. But they’re not willing to do this for Apple — because they need the remote exploit to have unfettered access to their own phones!

Apple has created a situation where someone acting in good faith to help iPhone users use their own devices has to keep security flaws away from Apple, so that they can also be used by malicious attackers. Apple and Apple’s users are on opposing sides — helping Apple hurts legitimate users, yet helping users jailbreak also means helping attackers exploit them.

What’s more, when Apple releases a patch to iOS to make it no longer vulnerable to these attacks, they will undoubtedly reverse the jailbreaks in the same patch. Thus, users will not want to install the patch, since it will kill functionality that they want on their phones! In the IT world, it’s hard enough to get people to patch even when there’s no downside, and Apple’s creating customers who deliberately avoid patches and updates, since most of Apple’s “security fixes” are aimed at protecting Apple from customers, not protecting customers from harm.

Come on, Apple, would a settings checkbox marked “Allow execution of unsigned code” be so bad? You could even pop up a warning that turning it on makes you ineligible for Apple support. Is it really better to force your userbase to help hackers?

attacks, industry, risk, society

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