ModPOS is new POS malware discovered in systems of US retailers after the rush of Thanksgiving. Experts speculate it is the most complex POS malware ever seen. Malware experts took three weeks to reverse engineer one of the three kernel modules of the malware, and the same malware experts only needed 30 minutes to reverse reverse engineer the Cheery Picker POS malware. Attackers have been operating since 2013, and in a very professional way, never raised any suspicion, and that this malware was only discovered after weeks of painful research, and reverse-engineering by malware experts.”]
Source: https://securityaffairs.co/wordpress/42220/cyber-crime/modpos-pos-malware.html