Security researchers Peter Dantini and Patrick Wardle recently discovered that Apple inadvertently notarized malicious payloads that were utilized in a recent adware campaign. OSX.Shlayer is a top common threat for Macs, making it the No. 1 Mac malware threat for 2019. The new malicious payload(s) appear to be nearly identical, containing OSXShlayer packaged with the Bundlore adware. The attackers ability to agilely continue their attack (with other attacks) is noteworthy, said Wardle.
Source: https://threatpost.com/apple-accidentally-notarizes-shlayer-malware/158818/