In Kali linux, there is an application called sendemail allowing users to send fake emails. Its usage is shown as follows:
sendemail -f source_email_address -t destination_email_address -u email_subject -m email_content -s email_server:email_service_port
Here is a sample for sending those mock emails.
#sendemail -f admin@facebook.com -t alex@gmail.com -u 'Your Facebook account is expired!' -m 'Please send back your Facebook account and password to hacker@gmail.com.' -s 192.168.1.10:25
