A new threat targeting Macs:

Malvertisers target Mac users with steganographic code stashed in images

Researchers have uncovered a recent malicious advertisement campaign that’s notable for its size, scope, and resourcefulness: a two-day blitz triggered as many as 5 million times per day that used highly camouflaged JavaScript stashed in images to install a trojan on visitors' Macs.

The ads were served by a group security firm Confiant has dubbed VeryMal, a name that comes from veryield-malyst.com, one of the ad-serving domains the group uses. A run that was active from January 11 to January 13 on about 25 of the top 100 publisher sites triggered the image as many as 5 million times a day. In an attempt to bypass increasingly effective measures available to detect malicious ads, the images used steganography—the ancient practice of hiding code, messages, or other data inside images or text—to deliver its malicious payload to Mac-using visitors.

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Security provider Malwarebytes assisted Confiant in the report by providing detailed analysis of the malware.

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....malvertisers continue to improve their techniques for slipping malicious content past advertisers who spend time and money to detect bad ads. Fortunately—for the moment, at least—most malicious ads seem to work by tricking visitors into clicking on OK buttons that will install malware. People who want to protect themselves should remain suspicious of any warning that displays while a Web advertisement is loaded. They should also ensure browsers and OSes are current and download updates only from official sources.

(ArsTechnica)

via ehMac.ca http://bit.ly/2S4NWk1