New phishing attack uses Morse code to hide malicious URLs By 10:40 AM A new targeted phishing campaign includes the novel obfuscation technique of using Morse code to hide malicious URLs in an email attachment. Samuel Morse and Alfred Vail invented morse code as a way of transmitting messages across telegraph wire. When using Morse code, each letter and number is encoded as a series of dots (short sound) and dashes (long sound). Starting last week, a threat actor began utilizing Morse code to hide malicious URLs in their phishing form to bypass secure mail gateways and mail filters. BleepingComputer could not find any references to Morse code being used in phishing attacks in the past, making this a novel obfuscation technique