Mac threat #1 is Yontoo Trojan Mar 20, 2013 | ESET CyberSecurity for Macs, General Security, Macintosh Viruses and TrojansAccording to Dr Web – the number one Mac threat at the moment is Yontoo Trojan Dr Web on Yontoo for Mac Yontoo hijacks web pages with adware and is detected by ESET CyberSecurity for Mac as Trojan software.