We fight against Spam! We have been the victim of a “Joe Job” attack. They are using spoofed sender data to generate an email that looks like it is from our domain.

If you have been receiving spam E-mail that appears to come from us, rest
assured that it was not sent from «adwedo». Recently,
we have been the victim of a “Joe Job” attack – and if you received one of
these E-mails, then you are yet another victim in the war against spam.

«adwedo» does not engage in spamming, and is an active
participant in the fight against those who do.

They are using spoofed sender data to generate an email that looks like it is from our domain. It is about as easy as putting a fake return address on a piece of postal mail. Unfortunately there is really no way to stop it. SPF can make it easier for other mail servers to identify email that actually comes from a domain and email that doesn’t, but just like you can’t stop someone from putting your postal address as the return address on all the spam letters/ads they mail, you can’t stop someone from putting our domain as the reply-to address on their spam.

SMTP just wasn’t designed to be secure, and it isn’t.

A “Joe Job” is the name given to an attack whereby a spammer sends unsolicited E-mail
which has been spoofed to appear as if it came from somebody else. The spammer is then
able to send spam without taking any of the responsibility for their actions, sending fallout
instead to the victim. Unethical companies may also engage in these tactics in an attempt to
defame their competition.

Whatever the reason, I’m sure you can agree that it needs to stop. This is why we are actively investigating
this attack to find out where they are coming from. Once we have discovered the culprit, we plan to
prosecute to the fullest extent of the law.

Joe Job on Wikipedia