A newly spotted Emotet Trojan sample features a Wi-Fi worm module that allows the malware to spread to new victims connected to nearby insecure networks. The worm uses wlanAPI.dll calls to discover wireless networks around an infected Wi-FI-enabled computer and attempt to brute-force its way in if they are password protected. Once it successfully connects the compromised device to another wireless network, the worm will start finding other Windows devices with non-hidden shares. The module not being discovered during the last two years despite researchers dissecting new strains on a daily basis.
Source: https://www.bleepingcomputer.com/news/security/emotet-hacks-nearby-wi-fi-networks-to-spread-to-new-victims/