Apple has pushed two updates today, to the data files used by XProtect, bringing its version number to 2132 dated 1 October 2020, and to its malware removal tool MRT, bringing it to version 1.67, also dated 1 October 2020.
Apple doesn’t release information about what these updates add or change, and now obfuscates the identities of malware detected by XProtect using internal code names.
Changes found in the XProtect Yara definitions include the addition of three new detections, of MACOS.8f20223, MACOS.1c119be and MACOS.e3548bb, and changes to the definitions for MACOS.8032420, MACOS.de444f2, MACOS.b70290c and MACOS.22d71e9.
You can check whether this update has been installed by opening System Information via About This Mac, and selecting the Installations item under Software.
A full listing of security data file versions is given by SilentKnight, LockRattler and SystHist for El Capitan, Sierra, High Sierra, Mojave, Catalina and Big Sur, available from their product page. If your Mac has not yet installed this update, you can force an update using SilentKnight, LockRattler, or at the command line.
I have updated the reference pages here which are accessed directly from LockRattler 4.2 and later using its Check blog button.
Note: several readers are reporting that MRT isn’t updated on older versions of macOS. As far as I’m aware, this is the first time that this has happened. If you have successfully updated MRT to 1.67 on High Sierra or earlier, please let me know in a comment here.