Westermo EDW-100 devices through 2024-05-03 have a hidden root user account with a hardcoded password that cannot be changed. NOTE: this is a serial-to-Ethernet converter that should not be placed at the edge of the network.
https://www.cisa.gov/news-events/ics-advisories/icsa-24-151-04
https://www.westermo.com/-/media/Files/Cyber-security/westermo_sa_EDW-100_24-05.pdf