The first week of 2018 saw global security flaws such as Meltdown and Spectre plaguing mobile and desktop CPUs. After releasing the macOS High Sierra 10.13.2 Supplemental Update in early January, Apple has on Tuesday released security updates for its older macOS versions - macOS Sierra and OS X El Capitan. These updates include patches for the Meltdown bug that emerged earlier this month. The updates are dubbed Security Update 2018-001. The macOS High Sierra 10.13.3 update has also been released for minor fixes.
Available on macOS High Sierra version 10.13.2, the security patch has now been rolled out to older macOS versions, macOS Sierra 10.12.6 and OS X El Capitan 10.11.6. While the update has modifications on several fronts such as audio, kernel, WebKit, and Wi-Fi, the most noticeable feature is the security patch against the Meltdown bug. The update also fixes issues like a maliciously crafted audio file leading to arbitrary code execution and one where an application could run arbitrary code using kernel privileges. Spectre vulnerabilities were taken care of with the earlier update in January, when Apple included security improvements to Safari (v11.0.2) and WebKit that were meant for macOS Sierra 10.12.6 and OS X El Capitan 10.11.6 apart from macOS High Sierra 10.13.2.
Additionally, Apple has also released macOS High Sierra version 10.13.3 that focuses on security, stability, and bug fixes. According to the update's release notes, it "Addresses an issue that could cause Messages conversations to temporarily be listed out of order" and "Resolves an issue that could cause your Mac to stop responding when connected to an SMB server."
Finally, Apple has also released an update to Safari (v11.0.3) that is available for OS X El Capitan 10.11.6, macOS Sierra 10.12.6, and macOS High Sierra 10.13.3. It fixes an issue where processing maliciously crafted Web content may lead to arbitrary code execution. Multiple memory corruption issues were addressed with improved memory handling.
How to install the latest macOS, OS X update
Updating your Mac device to the latest macOS, OS X version is simple. Launch the App Store on your Mac and search for "macOS" (go directly to this link for macOS High Sierra). Click on the macOS version you want to install, and click Download. Enter your Apple ID credentials in the provided box.
Once downloaded, an information window will pop up on your screen. Click on Continue and wait till the update automatically installs on your device. Installing the update will restart your computer.
On the mobile front, Apple has released the latest iOS 11.2.5 which comes with compatibility for HomePod (to be released on February 9) and news reading capabilities for virtual assistant Siri (only in UK, US, and Australia). A patch for Meltdown on iOS was released in early January.