For operational security, digital attackers are using Morse Code, a 177-year-old signaling technique.
From benign-looking communication channels to self-erasing operating systems, skilled cybercriminals use a variety of tactics to hide their traces on a target computer. However, digital attackers don’t commonly use Morse Code, a 177-year-old signaling technique, for operational security. Yet, as Microsoft researchers revealed on Thursday, this is exactly what happened during a year-long phishing campaign.
Source: https://www.cyberscoop.com/morse-code-microsoft-phishing/