Original: A corrupt client is thus able to forge this and gain access, as the rlogin protocol has no means of authenticating other machines' identities, or ensuring that the rlogin client on a trusted machine is the real rlogin client.
Simplified: A corrupt client is thus able to rebuild this and gain access. The protocol lakes all means of authenticating other machines' identities, or ensuring that the rlogin client is running on a trusted machine, or if it is the real rlogin client.