Some of the applications integrated into macOS support a preview function for certain file formats (e.g. image files). These include the Finder, the Safari browser, and the e-mail program integrated into macOS. The preview function automatically displays part of the attachment of an e-mail (for example) if the file format is known. An attacker could thus attempt to hide malicious code in an e-mail attachment. The preview function would display the e-mail attachment and possibly execute the malicious code, which in turn could compromise the Mac in question.