Around 10 years or so ago, at a previous employer, one could run any command as any other user, root included. No exploits, no custom binaries accepting command

Around 10 years or so ago, at a previous employer, one could run any command as any other user, root included. No exploits, no custom binaries accepting commands to be run as root. The cause? One character in the rlogin configs on all servers that allowed unathenticated access. Oops.