Apple has just pushed updates to its MRT and XProtect security tools for High Sierra, Sierra, and El Capitan.
XProtect‘s configuration data are updated to version 2096. Among the changes are that this now disables all versions of Adobe Flash Player older than the current version, 126.96.36.199. This is odd, because this very latest version of Flash Player doesn’t apparently contain any security enhancements over the previous one (188.8.131.52). Apple hadn’t incremented the Flash Player version requirement for a long time, though.
If you have just noticed that your Flash has been disabled, this means that your XProtect data are now up to date, but your Flash is not, and needs to be updated!
XProtect now supports detection of OSX.AdLoad.B.2 and OSX.Mughthesec.B, and recognises OSX.AdLoad.B as B.1 accordingly.
The configuration data for Apple’s Malware Removal Tool MRT have also been updated to version 1.25 in the same push, presumably supporting the removal of that malware.
You can check whether these updates have 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 LockRattler for Sierra and High Sierra, available from Downloads above.