The Importance of Email Encryption

Email - As private as sending a postcard...

You may already know that email is insecure; however, it may surprise you to learn just how insecure it really is. For example, did you know that messages which you thought were deleted years ago may be sitting on servers half-way around the world? Or that your messages can be read and modified in transit, even before they reach their destination? xcs_postcard

Sending an email message is like sending a postcard. When you send a postcard you drop it off at your local post office. Your local post office looks at the address and figures out which regional post office the letter should go to. Then the regional post office looks at the address and figures out which local post office is closest to your recipient. Finally, the recipient’s local post office delivers your postcard to its recipient. How many people could potentially read its contents before it reaches its intended recipient?

If you are writing a personal letter to that same friend or family member you sent the postcard to, you would be more inclined to seal it in an envelope.
If you are mailing a cheque to pay a bill or perhaps a letter telling a friend or family member that the extra key to your house is hidden under the large rock to the left of the back porch you might use a security envelope with hatched lines to obfuscate or hide the contents of the envelope even better. You might even send the letter via registered mail or even insure the contents of the package. Why then would you send personal or confidential information in an unprotected email? Sending information like the location of your extra house key under the large rock to the left of the back porch in an unencrypted email is the equivalent of writing it on a postcard for all to see.

And, computers are like post offices, and the SMTP is the procedure which an email post office uses to figure out where to send the letter next. Any program that sends an email message uses SMTP to deliver that message to the next “post office” for relaying to its final destination.

You never know how long it will take an email message to get from sender to recipient because you don’t know how busy the servers are, how much traffic there is on the Internet, what machines are down for maintenance, etc. Your messages may sit in queues on any number of servers for any amount of time. Some of these servers may belong to third parties (i.e. may not be under the purview of either the sender or the recipient) and could potentially mean that your message may be viewed by unauthorized parties.

There are many of the common security problems involved in communications, and email in particular. These threats include:

Eavesdropping: The Internet is a big place with a lot of people on it. It is very easy for someone who has access to the computers or networks through which your information is traveling to capture this information and read it. Just like someone in the next room listening in on your phone conversation, people using computers “near” the path your email takes through the Internet can potentially read and copy your messages!
Identity Theft: If someone can obtain the username and password that you use to access your email servers, they can read your email and send false email messages as you. Very often, these credentials can be obtained by eavesdropping on SMTP, POP, IMAP, or Webmail connections, by reading email messages in which you include this information, or through other means.
Message Modification: Anyone who has system administrator permission on any of the SMTP Servers that your message visits, can not only read your message, but they can delete or change the message before it continues on to its destination. Your recipient has no way to tell if the email message that you sent has been altered! If the message was merely deleted they wouldn’t even know it had been sent.
False Messages: It is very easy to construct messages that appear to be sent by someone else. Many viruses take advantage of this situation to propagate themselves. In general, there is no way to be sure that the apparent sender of a message is the true sender – the sender’s name could have been easily fabricated.
Message Replay: Just as a message can be modified, messages can be saved, modified, and re-sent later! You could receive a valid original message, but then receive subsequent faked messages that appear to be valid.
Unprotected Backups: Messages are stored in plain text on all SMTP Servers. Thus, backups of these servers’ disks contain plain text copies of your messages. As backups can be kept for years and can be read by anyone with access to them, your messages could still be exposed in insecure places even after you think that all copies have been “deleted”.
Repudiation: Because normal email messages can be forged, there is no way for you to prove that someone sent you a particular message. This means that even if someone DID send you a message, they can successfully deny it. This has implications with regards to using email for contracts, business communications, electronic commerce, etc.

You cannot tell if someone is reading your email or modifying messages subtly until it is too late. You cannot quantify the cost of email and information security problems until it is too late.

Find out how the WatchGuard XCS Solution can help...

The WatchGuard XCS (Extensible Content Security) appliances deliver the industry's most effective defense-in-depth solution for email security, web security and data loss prevention. These easy-to-use, all-in-one solutions offer the most effective defense from email and web-based threats including spam, viruses, malware, URL filtering, blended threats, spyware and network attacks.

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