A spam campaign pushing the info-stealing LokiBot trojan leverages a novel technique to avoid detection. According to researchers, the spam messages include malicious.zipx attachment hidden inside a.PNG file. LokiBot is a prolific trojan designed to siphon information from compromised endpoints. The malware is a commodity in underground markets, with versions selling for as little as $300. Attackers use the PNG file structure, complete with a.PNG header and IEND
Source: https://threatpost.com/lokibot-trojan-spotted-hitching-a-ride-inside-png-files/143491/

