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Apple iOS 13.4 offers fixes for 30 vulnerabilities

Apple has just announced its latest something for everyone security and feature updates for iOS, iPadOS, macOS, watchOS, and tvOS.

Apple has just announced its latest something for everyone security and feature updates for iOS, iPadOS, macOS, watchOS, and tvOS.
In terms of security, the attention grabber is iOS/iPad 13.4, which fixes 30 CVEs. Apple doesn’t rate the severity of vulnerabilities in its advisories, but we can pick out a few highlights from their descriptions.
The following apply to supported devices, namely the iPhone 6s and later, iPad Air 2 and later, iPad mini 4 and later, and iPod touch 7th generation.

Kernel bugs

The standout here is CVE-2020-9785, through which a rogue application could execute with kernel privileges, mirroring CVE-2020-3919, an identical-sounding issue connected to the IOHIDFamily.
A third kernel flaw fixed is CVE-2020-3914, information disclosure by reading restricted memory.


As usual, WebKit browser engine and Safari gave Apple plenty to fix, all but one of which were found by sources outside the company, including an arbitrary code execution flaw, CVE-2020-3899, credited to Google’s open source fuzzing tool, OSS-Fuzz.
Of the 10 CVEs in WebKit, another four allow arbitrary code execution, including CVE-2020-3901 and CVE-2020-9783, which could be exploited through maliciously crafted web content. The same goes for CVE-2020-3902, in which maliciously crafted content could make possible a cross-site scripting attack.
The Safari vulnerabilities, CVE-2020-9775 and CVE-2020-9781, are both relatively minor but unusual, the first causing a user’s private browsing history to be saved in the Screen Time parental control app, the second causing a user to “grant website permissions to a site they didn’t intend to.”
The WebKit fixes are mirrored in the desktop version of Safari.


Bluetooth is another interface that often causes problems. This time it’s CVE-2020-9770, through which an attacker with authenticated network access could intercept Bluetooth traffic from another iOS device.
A final one to watch is CVE-2020-3891, which an attacker with physical access to a locked iOS device could reply to messages even when that function is disabled.

macOS update

The macOS update takes Catalina to version 10.15.4 (security update 2020-002 for Mojave and High Sierra), fixing 27 CVE-level flaws.
Several of these are the same flaws fixed separately in iOS, namely CVE-2020-9785 and CVE-2020-3914 affecting the kernel, and CVE-2020-3919 in the IOHIDFamily.
Others include CVE-2019-14615, a low-priority fix for an Intel graphics driver vulnerability dating back to January, and CVE-2019-19232, an issue with sudo in the terminal window which could allow an attacker to run commands as a non-existent user.
And it wouldn’t be an Apple update without at least one fix for FaceTime, CVE-2020-3881.
Safari reaches 13.1 with fixes for 11 CVE bugs, all but one of which are, predictably, the same WebKit flaws fixed separately in iOS 13.4.

What to do?

To check you’re up to date:

  • On an iPhone or iPad, go to Settings > General > Software Update.
  • On a Mac, go to the Apple menu, choose About This Mac and click Software Update.

If your device has already updated automatically, you will see this on the update screen. If not, it will let you know about the update and offer to install it for you.

Latest Naked Security podcast


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“all bar one of which”??


I changed it to say “all but one”, to make the meaning clearer. (“Bar” is a synonym for “except” or “other than” when used this way – the sense is that of “bar”, as in the word “barrier”, meaning “to block” or “to exclude”. However, the word “but” is much more widely used and understood.)


Either the Safari 13.1 or the latest Mac OS security update when applied to High Sierra (10.13.6, released as part of the 10.15.4 update) is flawed. After installing both I got frequent cases of ‘Application Not Responding’, usually starting with Safari and eventually forcing a reboot. Rolling back to before these latest updates has stopped this frequent freezing. Beware.


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