Entries Tagged "Apple"

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More on Apple’s iPhone Backdoor

In this post, I’ll collect links on Apple’s iPhone backdoor for scanning CSAM images. Previous links are here and here.

Apple says that hash collisions in its CSAM detection system were expected, and not a concern. I’m not convinced that this secondary system was originally part of the design, since it wasn’t discussed in the original specification.

Good op-ed from a group of Princeton researchers who developed a similar system:

Our system could be easily repurposed for surveillance and censorship. The design wasn’t restricted to a specific category of content; a service could simply swap in any content-matching database, and the person using that service would be none the wiser.

EDITED TO ADD (8/30): Good essays by Matthew Green and Alex Stamos, Ross Anderson, Edward Snowden, and Susan Landau. And also Kurt Opsahl.

EDITED TO ADD (9/6): Apple is delaying implementation of the scheme.

Posted on August 20, 2021 at 8:54 AMView Comments

Apple’s NeuralHash Algorithm Has Been Reverse-Engineered

Apple’s NeuralHash algorithm—the one it’s using for client-side scanning on the iPhone—has been reverse-engineered.

Turns out it was already in iOS 14.3, and someone noticed:

Early tests show that it can tolerate image resizing and compression, but not cropping or rotations.

We also have the first collision: two images that hash to the same value.

The next step is to generate innocuous images that NeuralHash classifies as prohibited content.

This was a bad idea from the start, and Apple never seemed to consider the adversarial context of the system as a whole, and not just the cryptography.

Posted on August 18, 2021 at 11:51 AMView Comments

Apple Adds a Backdoor to iMessage and iCloud Storage

Apple’s announcement that it’s going to start scanning photos for child abuse material is a big deal. (Here are five news stories.) I have been following the details, and discussing it in several different email lists. I don’t have time right now to delve into the details, but wanted to post something.

EFF writes:

There are two main features that the company is planning to install in every Apple device. One is a scanning feature that will scan all photos as they get uploaded into iCloud Photos to see if they match a photo in the database of known child sexual abuse material (CSAM) maintained by the National Center for Missing & Exploited Children (NCMEC). The other feature scans all iMessage images sent or received by child accounts—that is, accounts designated as owned by a minor—for sexually explicit material, and if the child is young enough, notifies the parent when these images are sent or received. This feature can be turned on or off by parents.

This is pretty shocking coming from Apple, which is generally really good about privacy. It opens the door for all sorts of other surveillance, since now that the system is built it can be used for all sorts of other messages. And it breaks end-to-end encryption, despite Apple’s denials:

Does this break end-to-end encryption in Messages?

No. This doesn’t change the privacy assurances of Messages, and Apple never gains access to communications as a result of this feature. Any user of Messages, including those with with communication safety enabled, retains control over what is sent and to whom. If the feature is enabled for the child account, the device will evaluate images in Messages and present an intervention if the image is determined to be sexually explicit. For accounts of children age 12 and under, parents can set up parental notifications which will be sent if the child confirms and sends or views an image that has been determined to be sexually explicit. None of the communications, image evaluation, interventions, or notifications are available to Apple.

Notice Apple changing the definition of “end-to-end encryption.” No longer is the message a private communication between sender and receiver. A third party is alerted if the message meets a certain criteria.

This is a security disaster. Read tweets by Matthew Green and Edward Snowden. Also this. I’ll post more when I see it.

Beware the Four Horsemen of the Information Apocalypse. They’ll scare you into accepting all sorts of insecure systems.

EDITED TO ADD: This is a really good write-up of the problems.

EDITED TO ADD: Alex Stamos comments.

An open letter to Apple criticizing the project.

A leaked Apple memo responding to the criticisms. (What are the odds that Apple did not intend this to leak?)

EDITED TO ADD: John Gruber’s excellent analysis.

EDITED TO ADD (8/11): Paul Rosenzweig wrote an excellent policy discussion.

EDITED TO ADD (8/13): Really good essay by EFF’s Kurt Opsahl. Ross Anderson did an interview with Glenn Beck. And this news article talks about dissent within Apple about this feature.

The Economist has a good take. Apple responds to criticisms. (It’s worth watching the Wall Street Journal video interview as well.)

EDITED TO ADD (8/14): Apple released a threat model

EDITED TO ADD (8/20): Follow-on blog posts here and here.

Posted on August 10, 2021 at 6:37 AMView Comments

Apple Will Offer Onion Routing for iCloud/Safari Users

At this year’s Apple Worldwide Developer Conference, Apple announced something called “iCloud Private Relay.” That’s basically its private version of onion routing, which is what Tor does.

Privacy Relay is built into both the forthcoming iOS and MacOS versions, but it will only work if you’re an iCloud Plus subscriber and you have it enabled from within your iCloud settings.

Once it’s enabled and you open Safari to browse, Private Relay splits up two pieces of information that—when delivered to websites together as normal—could quickly identify you. Those are your IP address (who and exactly where you are) and your DNS request (the address of the website you want, in numeric form).

Once the two pieces of information are split, Private Relay encrypts your DNS request and sends both the IP address and now-encrypted DNS request to an Apple proxy server. This is the first of two stops your traffic will make before you see a website. At this point, Apple has already handed over the encryption keys to the third party running the second of the two stops, so Apple can’t see what website you’re trying to access with your encrypted DNS request. All Apple can see is your IP address.

Although it has received both your IP address and encrypted DNS request, Apple’s server doesn’t send your original IP address to the second stop. Instead, it gives you an anonymous IP address that is approximately associated with your general region or city.

Not available in China, of course—and also Belarus, Colombia, Egypt, Kazakhstan, Saudi Arabia, South Africa, Turkmenistan, Uganda, and the Philippines.

Posted on June 22, 2021 at 6:54 AMView Comments

Serious MacOS Vulnerability Patched

Apple just patched a MacOS vulnerability that bypassed malware checks.

The flaw is akin to a front entrance that’s barred and bolted effectively, but with a cat door at the bottom that you can easily toss a bomb through. Apple mistakenly assumed that applications will always have certain specific attributes. Owens discovered that if he made an application that was really just a script—code that tells another program what do rather than doing it itself—and didn’t include a standard application metadata file called “info.plist,” he could silently run the app on any Mac. The operating system wouldn’t even give its most basic prompt: “This is an application downloaded from the Internet. Are you sure you want to open it?”


Posted on April 30, 2021 at 7:38 AMView Comments

Details on the Unlocking of the San Bernardino Terrorist’s iPhone

The Washington Post has published a long story on the unlocking of the San Bernardino Terrorist’s iPhone 5C in 2016. We all thought it was an Israeli company called Cellebrite. It was actually an Australian company called Azimuth Security.

Azimuth specialized in finding significant vulnerabilities. Dowd, a former IBM X-Force researcher whom one peer called “the Mozart of exploit design,” had found one in open-source code from Mozilla that Apple used to permit accessories to be plugged into an iPhone’s lightning port, according to the person.


Using the flaw Dowd found, Wang, based in Portland, Ore., created an exploit that enabled initial access to the phone ­ a foot in the door. Then he hitched it to another exploit that permitted greater maneuverability, according to the people. And then he linked that to a final exploit that another Azimuth researcher had already created for iPhones, giving him full control over the phone’s core processor ­ the brains of the device. From there, he wrote software that rapidly tried all combinations of the passcode, bypassing other features, such as the one that erased data after 10 incorrect tries.

Apple is suing various companies over this sort of thing. The article goes into the details.

Posted on April 19, 2021 at 6:08 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.