Email Security

daniel1113

Diamond Member
Jun 6, 2003
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I am part of a law research team at the The College of William & Mary Law School. Each year, we carry out various lab trials to show the latest uses of technology in court rooms. This year, we are focusing on detecting digital forgeries, specifically email.

While I am pretty knowledgeable when it comes to technology, I am by no means a security expert, and was hoping there might be a few AT members that could offer me some guidance.

Basically, as part of our trial, we want to show that a third-party can send a forged email from his/her own computer that would look like an original email being sent from a target user's machine. I am well aware of ease in which email header's can be altered, IP and MAC addresses can be spoofed, etc. It would be pretty simple for an attacker to remotely connect to a target machine and send emails from that machine. However, we want to take it further than that and assume that the attacker does not have access to a user's machine, either physically or over a network (at least not at the time that the email is sent). So, the email must originate on the attacker's machine and be sent through whatever connection he is using at the time.

Before I start doing any in-depth research and getting third-parties to help with the trial, here's what I want to know: is it reasonably possible for a savvy third-party attacker to send a forged email from his/her own computer that would look like an original email being sent from a target user's machine at all points along the delivery path (i.e., as the message is traversed through various servers, ISPs, etc.)?

I am not looking for any details about how it would be done or anything like that. I just want to see how far we can push this trial while remaining realistic. Thanks in advance!
 

n0cmonkey

Elite Member
Jun 10, 2001
42,936
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Anything is possible. However, it would be rather difficult to forge it perfectly. There's usually some clue (no matter how small) that an email has been forged. IP of the sending SMTP server is one example of something that can be hard to forge.
 

RebateMonger

Elite Member
Dec 24, 2005
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I'm not a specialist in such things, but the IP address of the originating mail server is difficult/impossible to forge. Everything else can usually be forged.
 

seepy83

Platinum Member
Nov 12, 2003
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A poorly configured SMTP server that allows Relays could solve the problem of the Source Address not being correct, but that is very unlikely to occur. Forging an IP is pretty simple on a LAN, but basically impossible on the Internet (assuming that you cannot exploit the ISP).

Like n0c and Rebate already said, from my experience there is always something that someone with enough knowledge will be able to pick up on.
 

daniel1113

Diamond Member
Jun 6, 2003
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This is pretty much what I have concluded as well. If the attacker has access to the user's network, the IP could be forged without too much effort. If done through the internet, success pretty much hinges on what information is stored by the ISP and the amount of time that information is kept, or having access to the ISP's server.

Thanks for the replies.