Apple’s newly released iOS 12.1.4 includes fixes for two serious vulnerabilities that are already used by hackers. The update also fixes the FaceTime bug that allowed users to remote enable other peoples’ microphones.
One flaw, CVE-2019-7286, is a memory corruption issue in the Foundation component that can allow an application to gain elevated privileges. The other, CVE-2019-7287, allows an application to execute arbitrary code with kernel privileges.
It’s not clear in what type of attacks these vulnerabilities have been exploited before Apple patched them, but zero-day iOS exploit chains that can lead to a full device compromise are worth $2 million on the exploit acquisition market.
The iPhone is seen as the most secure smartphone and the people who use it are typically high-value targets. Law enforcement, intelligence agencies, cyberespionage groups and cybercriminal gangs are always interested in acquiring such exploits.
The new iOS update also patches a bug in the FaceTime video calling app that was recently publicly disclosed and which can be used to remotely turn on the microphone on the recipients’ devices. The bug is related to the FaceTime group chat feature, so Apple disabled that functionality on its servers after the issue became public to prevent abuse. Now, the client-side issue has also been fixed, so the group chat feature can be safely used again.
“A logic issue existed in the handling of Group FaceTime calls,” Apple said in its advisory. “The issue was addressed with improved state management.”
A second vulnerability located in the Live Photos feature of FaceTime has also been patched with this update. That flaw was discovered internally after Apple performed a thorough security audit of the FaceTime service, probably in response to the group chat issue.
The two FaceTime bugs and the Foundation vulnerability, CVE-2019-7286, have also been fixed through a supplemental update to macOS Mojave 10.14.3 that was also released this week.
Low-end Android Devices Get Full-Disk Encryption
Google has developed a new encryption mode that makes it possible to enable full-disk encryption on low-end Android devices that don’t have CPUs with hardware-based cryptographic acceleration.
Called Adiantum, the new mode allows using the fast ChaCha20 stream cipher for full-disk encryption, something that wasn’t possible until now because of limitations in the way this cipher operates.
Android’s current full-disk encryption functionality relies on the AES cipher, which has very good performance on processors that have hardware support for it, such as those based on the ARMv8 architecture.
However, many low-end Android devices, including phones, tablets, smartwatches and TVs, have older CPUs such as ARM Cortex-A7 that do not have AES hardware instructions. Until now, using Android’s full-disk encryption on such devices would have required performing AES operations in software, which would have severely impacted their performance.
Meanwhile, the ChaCha20 cipher, which is used to encrypt data streams—for example, in HTTPS—is very fast on all CPUs because it only relies on operations like additions, rotations and XORs that all CPUs support natively. The problem was that it couldn’t be used to encrypt blocks of data like those that storage devices operate with.
“Adiantum allows us to use the ChaCha stream cipher in a length-preserving mode, by adapting ideas from AES-based proposals for length-preserving encryption such as HCTR and HCH,” Paul Crowley and Eric Biggers from the Android Security and Privacy Team said in a blog post. “On ARM Cortex-A7, Adiantum encryption and decryption on 4096-byte sectors is about 10.6 cycles per byte, around 5x faster than AES-256-XTS.”
The new encryption mode has been integrated into Android Pie so low-end devices that get updated to this Android version will be able to use full-disk encryption. In addition, Adiantum has been integrated into the upcoming Linux 5 kernel, so any embedded Linux device that will use this kernel version will also be able to use it for encrypting storage.