A new Brazilian Trojan tries to conceal the malicious files in a PNG image. The attack starts with a simple phishing PDF and directs the user to the malicious file. This type of attack was publicized several months ago in the US and now they are using the same method in Brazil. This technique allows the criminals to successfully hide the binary inside a file that appears to be a PNG. It also makes the analysis process harder for antivirus companies as well as bypassing the automated process to detect malicious files on hosting servers.”]
Source: https://securelist.com/png-embedded-malicious-payload-hidden-in-a-png-file/74297/