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Schneier on Security: Blog Entries Tagged Apple

Schneier on Security

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Entries Tagged “Apple”

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iOS 12.1 Vulnerability

This is really just to point out that computer security is really hard:

Almost as soon as Apple released iOS 12.1 on Tuesday, a Spanish security researcher discovered a bug that exploits group Facetime calls to give anyone access to an iPhone users' contact information with no need for a passcode.

[...]

A bad actor would need physical access to the phone that they are targeting and has a few options for viewing the victim's contact information. They would need to either call the phone from another iPhone or have the phone call itself. Once the call connects they would need to:

  • Select the Facetime icon
  • Select "Add Person"
  • Select the plus icon
  • Scroll through the contacts and use 3D touch on a name to view all contact information that's stored.

Making the phone call itself without entering a passcode can be accomplished by either telling Siri the phone number or, if they don't know the number, they can say "call my phone." We tested this with both the owners' voice and a strangers voice, in both cases, Siri initiated the call.

Posted on November 8, 2018 at 6:35 AMView Comments

Defeating the iPhone Restricted Mode

Recently, Apple introduced restricted mode to protect iPhones from attacks by companies like Cellebrite and Greyshift, which allow attackers to recover information from a phone without the password or fingerprint. Elcomsoft just announced that it can easily bypass it.

There is an important lesson in this: security is hard. Apple Computer has one of the best security teams on the planet. This feature was not tossed out in a day; it was designed and implemented with a lot of thought and care. If this team could make a mistake like this, imagine how bad a security feature is when implemented by a team without this kind of expertise.

This is the reason actual cryptographers and security engineers are very skeptical when a random company announces that their product is "secure." We know that they don't have the requisite security expertise to design and implement security properly. We know they didn't take the time and care. We know that their engineers think they understand security, and designed to a level that they couldn't break.

Getting security right is hard for the best teams on the world. It's impossible for average teams.

Posted on July 18, 2018 at 6:25 AMView Comments

Bypassing Passcodes in iOS

Last week, a story was going around explaining how to brute-force an iOS password. Basically, the trick was to plug the phone into an external keyboard and trying every PIN at once:

We reported Friday on Hickey's findings, which claimed to be able to send all combinations of a user's possible passcode in one go, by enumerating each code from 0000 to 9999, and concatenating the results in one string with no spaces. He explained that because this doesn't give the software any breaks, the keyboard input routine takes priority over the device's data-erasing feature.

I didn't write about it, because it seemed too good to be true. A few days later, Apple pushed back on the findings -- and it seems that it doesn't work.

This isn't to say that no one can break into an iPhone. We know that companies like Cellebrite and Grayshift are renting/selling iPhone unlock tools to law enforcement -- which means governments and criminals can do the same thing -- and that Apple is releasing a new feature called "restricted mode" that may make those hacks obsolete.

Grayshift is claiming that its technology will still work.

Former Apple security engineer Braden Thomas, who now works for a company called Grayshift, warned customers who had bought his GrayKey iPhone unlocking tool that iOS 11.3 would make it a bit harder for cops to get evidence and data out of seized iPhones. A change in the beta didn't break GrayKey, but would require cops to use GrayKey on phones within a week of them being last unlocked.

"Starting with iOS 11.3, iOS saves the last time a device has been unlocked (either with biometrics or passcode) or was connected to an accessory or computer. If a full seven days (168 hours) elapse [sic] since the last time iOS saved one of these events, the Lightning port is entirely disabled," Thomas wrote in a blog post published in a customer-only portal, which Motherboard obtained. "You cannot use it to sync or to connect to accessories. It is basically just a charging port at this point. This is termed USB Restricted Mode and it affects all devices that support iOS 11.3."

Whether that's real or marketing, we don't know.

Posted on June 26, 2018 at 9:38 AMView Comments

Perverse Vulnerability from Interaction between 2-Factor Authentication and iOS AutoFill

Apple is rolling out an iOS security usability feature called Security code AutoFill. The basic idea is that the OS scans incoming SMS messages for security codes and suggests them in AutoFill, so that people can use them without having to memorize or type them.

Sounds like a really good idea, but Andreas Gutmann points out an application where this could become a vulnerability: when authenticating transactions:

Transaction authentication, as opposed to user authentication, is used to attest the correctness of the intention of an action rather than just the identity of a user. It is most widely known from online banking, where it is an essential tool to defend against sophisticated attacks. For example, an adversary can try to trick a victim into transferring money to a different account than the one intended. To achieve this the adversary might use social engineering techniques such as phishing and vishing and/or tools such as Man-in-the-Browser malware.

Transaction authentication is used to defend against these adversaries. Different methods exist but in the one of relevance here -- which is among the most common methods currently used -- the bank will summarise the salient information of any transaction request, augment this summary with a TAN tailored to that information, and send this data to the registered phone number via SMS. The user, or bank customer in this case, should verify the summary and, if this summary matches with his or her intentions, copy the TAN from the SMS message into the webpage.

This new iOS feature creates problems for the use of SMS in transaction authentication. Applied to 2FA, the user would no longer need to open and read the SMS from which the code has already been conveniently extracted and presented. Unless this feature can reliably distinguish between OTPs in 2FA and TANs in transaction authentication, we can expect that users will also have their TANs extracted and presented without context of the salient information, e.g. amount and destination of the transaction. Yet, precisely the verification of this salient information is essential for security. Examples of where this scenario could apply include a Man-in-the-Middle attack on the user accessing online banking from their mobile browser, or where a malicious website or app on the user's phone accesses the bank's legitimate online banking service.

This is an interesting interaction between two security systems. Security code AutoFill eliminates the need for the user to view the SMS or memorize the one-time code. Transaction authentication assumes the user read and approved the additional information in the SMS message before using the one-time code.

Posted on June 20, 2018 at 6:51 AMView Comments

Russian Censorship of Telegram

Internet censors have a new strategy in their bid to block applications and websites: pressuring the large cloud providers that host them. These providers have concerns that are much broader than the targets of censorship efforts, so they have the choice of either standing up to the censors or capitulating in order to maximize their business. Today's Internet largely reflects the dominance of a handful of companies behind the cloud services, search engines and mobile platforms that underpin the technology landscape. This new centralization radically tips the balance between those who want to censor parts of the Internet and those trying to evade censorship. When the profitable answer is for a software giant to acquiesce to censors' demands, how long can Internet freedom last?

The recent battle between the Russian government and the Telegram messaging app illustrates one way this might play out. Russia has been trying to block Telegram since April, when a Moscow court banned it after the company refused to give Russian authorities access to user messages. Telegram, which is widely used in Russia, works on both iPhone and Android, and there are Windows and Mac desktop versions available. The app offers optional end-to-end encryption, meaning that all messages are encrypted on the sender's phone and decrypted on the receiver's phone; no part of the network can eavesdrop on the messages.

Since then, Telegram has been playing cat-and-mouse with the Russian telecom regulator Roskomnadzor by varying the IP address the app uses to communicate. Because Telegram isn't a fixed website, it doesn't need a fixed IP address. Telegram bought tens of thousands of IP addresses and has been quickly rotating through them, staying a step ahead of censors. Cleverly, this tactic is invisible to users. The app never sees the change, or the entire list of IP addresses, and the censor has no clear way to block them all.

A week after the court ban, Roskomnadzor countered with an unprecedented move of its own: blocking 19 million IP addresses, many on Amazon Web Services and Google Cloud. The collateral damage was widespread: The action inadvertently broke many other web services that use those platforms, and Roskomnadzor scaled back after it became clear that its action had affected services critical for Russian business. Even so, the censor is still blocking millions of IP addresses.

More recently, Russia has been pressuring Apple not to offer the Telegram app in its iPhone App Store. As of this writing, Apple has not complied, and the company has allowed Telegram to download a critical software update to iPhone users (after what the app's founder called a delay last month). Roskomnadzor could further pressure Apple, though, including by threatening to turn off its entire iPhone app business in Russia.

Telegram might seem a weird app for Russia to focus on. Those of us who work in security don't recommend the program, primarily because of the nature of its cryptographic protocols. In general, proprietary cryptography has numerous fatal security flaws. We generally recommend Signal for secure SMS messaging, or, if having that program on your computer is somehow incriminating, WhatsApp. (More than 1.5 billion people worldwide use WhatsApp.) What Telegram has going for it is that it works really well on lousy networks. That's why it is so popular in places like Iran and Afghanistan. (Iran is also trying to ban the app.)

What the Russian government doesn't like about Telegram is its anonymous broadcast feature­ -- channel capability and chats -- ­which makes it an effective platform for political debate and citizen journalism. The Russians might not like that Telegram is encrypted, but odds are good that they can simply break the encryption. Telegram's role in facilitating uncontrolled journalism is the real issue.

Iran attempts to block Telegram have been more successful than Russia's, less because Iran's censorship technology is more sophisticated but because Telegram is not willing to go as far to defend Iranian users. The reasons are not rooted in business decisions. Simply put, Telegram is a Russian product and the designers are more motivated to poke Russia in the eye. Pavel Durov, Telegram's founder, has pledged millions of dollars to help fight Russian censorship.

For the moment, Russia has lost. But this battle is far from over. Russia could easily come back with more targeted pressure on Google, Amazon and Apple. A year earlier, Zello used the same trick Telegram is using to evade Russian censors. Then, Roskomnadzor threatened to block all of Amazon Web Services and Google Cloud; and in that instance, both companies forced Zello to stop its IP-hopping censorship-evasion tactic.

Russia could also further develop its censorship infrastructure. If its capabilities were as finely honed as China's, it would be able to more effectively block Telegram from operating. Right now, Russia can block only specific IP addresses, which is too coarse a tool for this issue. Telegram's voice capabilities in Russia are significantly degraded, however, probably because high-capacity IP addresses are easier to block.

Whatever its current frustrations, Russia might well win in the long term. By demonstrating its willingness to suffer the temporary collateral damage of blocking major cloud providers, it prompted cloud providers to block another and more effective anti-censorship tactic, or at least accelerated the process. In April, Google and Amazon banned­ -- and technically blocked­ -- the practice of "domain fronting," a trick anti-censorship tools use to get around Internet censors by pretending to be other kinds of traffic. Developers would use popular websites as a proxy, routing traffic to their own servers through another website­ -- in this case Google.com­ -- to fool censors into believing the traffic was intended for Google.com. The anonymous web-browsing tool Tor has used domain fronting since 2014. Signal, since 2016. Eliminating the capability is a boon to censors worldwide.

Tech giants have gotten embroiled in censorship battles for years. Sometimes they fight and sometimes they fold, but until now there have always been options. What this particular fight highlights is that Internet freedom is increasingly in the hands of the world's largest Internet companies. And while freedom may have its advocates -- ­the American Civil Liberties Union has tweeted its support for those companies, and some 12,000 people in Moscow protested against the Telegram ban­ -- actions such as disallowing domain fronting illustrate that getting the big tech companies to sacrifice their near-term commercial interests will be an uphill battle. Apple has already removed anti-censorship apps from its Chinese app store.

In 1993, John Gilmore famously said that "The Internet interprets censorship as damage and routes around it." That was technically true when he said it but only because the routing structure of the Internet was so distributed. As centralization increases, the Internet loses that robustness, and censorship by governments and companies becomes easier.

This essay previously appeared on Lawfare.com.

Posted on June 13, 2018 at 6:55 AMView Comments

New iPhone OS May Include Device-Unlocking Security

iOS 12, the next release of Apple's iPhone operating system, may include features to prevent someone from unlocking your phone without your permission:

The feature essentially forces users to unlock the iPhone with the passcode when connecting it to a USB accessory everytime the phone has not been unlocked for one hour. That includes the iPhone unlocking devices that companies such as Cellebrite or GrayShift make, which police departments all over the world use to hack into seized iPhones.

"That pretty much kills [GrayShift's product] GrayKey and Cellebrite," Ryan Duff, a security researcher who has studied iPhone and is Director of Cyber Solutions at Point3 Security, told Motherboard in an online chat. "If it actually does what it says and doesn't let ANY type of data connection happen until it's unlocked, then yes. You can't exploit the device if you can't communicate with it."

This is part of a bunch of security enhancements in iOS 12:

Other enhancements include tools for generating strong passwords, storing them in the iCloud keychain, and automatically entering them into Safari and iOS apps across all of a user's devices. Previously, standalone apps such as 1Password have done much the same thing. Now, Apple is integrating the functions directly into macOS and iOS. Apple also debuted new programming interfaces that allow users to more easily access passwords stored in third-party password managers directly from the QuickType bar. The company also announced a new feature that will flag reused passwords, an interface that autofills one-time passwords provided by authentication apps, and a mechanism for sharing passwords among nearby iOS devices, Macs, and Apple TVs.

A separate privacy enhancement is designed to prevent websites from tracking people when using Safari. It's specifically designed to prevent share buttons and comment code on webpages from tracking people's movements across the Web without permission or from collecting a device's unique settings such as fonts, in an attempt to fingerprint the device.

The last additions of note are new permission dialogues macOS Mojave will display before allowing apps to access a user's camera or microphone. The permissions are designed to thwart malicious software that surreptitiously turns on these devices in an attempt to spy on users. The new protections will largely mimic those previously available only through standalone apps such as one called Oversight, developed by security researcher Patrick Wardle. Apple said similar dialog permissions will protect the file system, mail database, message history, and backups.

Posted on June 12, 2018 at 6:23 AMView Comments

Sending Inaudible Commands to Voice Assistants

Researchers have demonstrated the ability to send inaudible commands to voice assistants like Alexa, Siri, and Google Assistant.

Over the last two years, researchers in China and the United States have begun demonstrating that they can send hidden commands that are undetectable to the human ear to Apple's Siri, Amazon's Alexa and Google's Assistant. Inside university labs, the researchers have been able to secretly activate the artificial intelligence systems on smartphones and smart speakers, making them dial phone numbers or open websites. In the wrong hands, the technology could be used to unlock doors, wire money or buy stuff online ­-- simply with music playing over the radio.

A group of students from University of California, Berkeley, and Georgetown University showed in 2016 that they could hide commands in white noise played over loudspeakers and through YouTube videos to get smart devices to turn on airplane mode or open a website.

This month, some of those Berkeley researchers published a research paper that went further, saying they could embed commands directly into recordings of music or spoken text. So while a human listener hears someone talking or an orchestra playing, Amazon's Echo speaker might hear an instruction to add something to your shopping list.

Posted on May 15, 2018 at 6:13 AMView Comments

Computer Alarm that Triggers When Lid Is Opened

"Do Not Disturb" is a Macintosh app that send an alert when the lid is opened. The idea is to detect computer tampering.

Wired article:

Do Not Disturb goes a step further than just the push notification. Using the Do Not Disturb iOS app, a notified user can send themselves a picture snapped with the laptop's webcam to catch the perpetrator in the act, or they can shut down the computer remotely. The app can also be configured to take more custom actions like sending an email, recording screen activity, and keeping logs of commands executed on the machine.

Can someone please make one of these for Windows?

Posted on April 24, 2018 at 6:04 AMView Comments

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