Possible impersonation backdoor in Exim

Lets say that one company has site with contact page where emails are shown: contact@somecompany.com, support@somecompany.com.

I have found that Exim from DA (newest, without any customization) enables u to send email from AS contact@somecompany.com TO support@somecomapany.com without authentification (mail sent from other server/IP).

Such impersonation souldnt be possible. I could send 10000 or even more mails without authentification to that user...

Example log: http://wklej.org/hash/78a2cbd5ce8/txt/

Also tested on other hosting companies servers that have DA, same problem every server.

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