Apple has released an update to XProtect
Overnight, Apple released an update to XProtect for all versions of macOS from El Capitan or so, bringing it to version 2183.
Apple doesn’t release information about what security issues this update might add or change. XProtect’s Yara definitions replace the rule for MACOS.PIRRIT.HI with a (different) rule for MACOS.REALSTAR, and amend the existing rule for MACOS.SOMA.D.
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 to Sonoma available from their product page. If your Mac hasn’t yet installed this update, you can force it using SilentKnight, LockRattler, or at the command line.
If you want to install this as a named update in SilentKnight, its label is XProtectPlistConfigData_10_15-2183.
I have updated the reference pages here which are accessed directly from LockRattler 4.2 and later using its Check blog button.
I maintain lists of the current versions of security data files for Sonoma on this page, Ventura on this page, Monterey on this page, Big Sur on this page, Catalina on this page, Mojave on this page, High Sierra on this page, Sierra on this page, and El Capitan on this page.