can valid email addresses contain hacker commands embedded especially for sendmail servers?

I suspect that the RFC 2822  standards allow some shady email address sequences.
Can anyone confirm this and suggest a remedy to the problem?

I imagine I could validate and then do a check for any odd characters not typical
Perhaps sequences like  cmd\  may do something rather nasty.
Perhaps someone has some ideas about this particularly which of the nasty punctuation characters
make this possible
Robert SilverSr. Software EngineerAsked:
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Not really. Sendmail will really only do 2 possible things, although none are set up be default: deliver mail to local users, forward mail along for an external user. You can deliver a message to a program (like a mailing list application or something, but any program that is handled by sendmail uses a special restricted shell and must be in a special directory (ex: /etc/smrsh).

Sure if an attacker put a malicious program (think "rm -rf /" in the /etc/smrsh folder and then setup an alias to that program it might do some damage, but in order to do that, they'd already need the access to do the damage in the first place. And still, I don't know what the restricted shell will allow, it might not allow operations that are damaging to the system.

I wouldn't worry about it, as long as you tighten up your server (restrict relaying).

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Robert SilverSr. Software EngineerAuthor Commented:
Again I still find it odd that  such email addresses are possible
320 character email addresses? unbelivable.
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