Complex sentence: SSH was designed as a replacement for Telnet and other insecure remote shell protocols such as the Berkeley rlogin, rsh, and rexec protocols, which send information, notably passwords, in plaintext, rendering them susceptible to interception and disclosure using packet analysis.
Split into simpler sentences: SSH was designed as a replacement for Telnet and for insecure remote shell protocols such as the Berkeley rlogin, rsh, and rexec protocols. Those protocols send information, notably passwords, in plaintext, rendering them susceptible to interception and disclosure using packet analysis.