Don’t know of any publicaly available tools but if you’re wanting to spoof email, it can be simply achieved with a telnet/netcat client and a basic understanding of the protocol. Once you’ve got it down it’s simple to script/code to do the job for you. Works wonders for user awareness testing 😀
Perhaps the simplest way is to configure the From: address in a mail client and spoof emails that way. This is how I first spoofed mails back in the ’90s when SMTP servers didn’t really care who you said you were. If you’re connecting to a permissive enough mail server then this technique might work.
If you’re serious about learning security then learn to speak SMTP. It’s a valuable skill for testing and debugging mail servers as well as a means of spending prank mail.
I will have to look into it… but I know I was reading not long ago about a couple of programs specifically for crafting faked up emails with spoofed headers etc. And imbedded links that lead to (if your corp) a corporate web site to teach users about the hazards of clicking on links from unknown sources. Kind of a user training tool. The one program I looked at seemed decent, but I forget what the name was. One of the problems with getting old.