Send email with attachment in C++

Question

I am working on a project in C++, which includes a feature of sending information to someone as \'email attachment\'.

Everything is done except this \'email\' thing.

Answer 1

Kudos to you for trying to code it yourself. This lifts you above the average script kiddy.

But shame yourself on spying on your brother. His private business is HIS business and none of yours.

Also, if your brother is only a bit clever, he'll not fall for some executable email attachment. Additionally, most email programs and webmailers will warn against executing this thing. If you were to make this foolproof you'd need to find vulnerabilities in the email client(s) used, to inject code, best way to go is attacking image loader and compression routines, but you'll have to find a 0day ideally, otherwise those exploits may have been patched before you get your spyware out. Some topics you may want to read upon are

• stack overflow exploits
• heap spraying
• return based programming (used to counter W^X protection and mild implementations of address space randomization)

Sending email boils down to implement the SMTP protocol documented in http://www.faqs.org/rfcs/rfc821.html

Technically one could send an email directly to a target server, but those will usually reject mails coming directly from dialup connections, since this is a cheap yet effective method to counter spam. So you better go over an MTA with proper MX records. Freemailers are your friend, Hotmail is very popular for this. However you'll have to implement SMTP-Auth then, too. Documented in http://www.faqs.org/rfcs/rfc2554.html

Of course instead of sending an email you could as well just upload a file somewhere. Or you could implement IMAP and use a IMAP capable freemailer to store the data in the IMAP Drafts directory.

So if you manage to pull this off yourself, with your own code, then I think you deserve the success, but only if this doesn't involve third party libraries of malware construction kits (yes they exist).