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72 Chapter 2 • General Security Concepts: Attacks
EXERCISE 2.02
E-MAIL SPOOFING
It is almost trivial to spoof an e-mail’s sender address, and we can show
you how using any e-mail client (e.g., Microsoft Outlook Express).
Normally, you define e-mail accounts in Outlook Express, including your
name, e-mail address, password, and mail server. However, in most cases,
to send an e-mail the password is not used, as most Simple Mail Transfer
Protocol (SMTP) traffic is not authenticated.
Let’s say you want to send your colleague an e-mail as if it was sent
from a Dr. Sam Carter, from a fictitious government agency. First, you
need to find out the mail server your colleague receives e-mail from.
Open a command prompt and type nslookup, then input the set
type=MX command, and enter the domain name of the e-mail address.
You should get a listing like this:
Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.
C:\Documents and Settings\user>nslookup
Default Server: dns.yourdomain.com
Address: 10.1.1.1
> set type=MX
> destinationdomain.com
Server: dns.yourdomain.com
Address: 10.1.1.1
Non-authoritative answer:
destinationdomain.com MX preference = 10, mail exchanger =
mail.destinationdomain.com
destinationdomain.com MX preference = 20, mail exchanger =
mail2.destinationdomain.com
destinationdomain.com nameserver = ns1.domainserver.com
mail.destinationdomain.com internet address = 172.16.1.1
mail2.destinationdomain.com internet address = 172.16.2.1
>
www.syngress.com
