One of the challenges for businesses when they provide email access to their staff is how to let staff use email productively while also managing the risk of information leakage.

Although information leaks can occur over many different mediums, leaks over email remain a serious concern for some businesses.

Fortunately Exchange Server 2010 includes features to help organizations manage the risk of information leaks via email.

Using Message Classifications

Message classifications provide a mechanism by which end users can classify individual email messages.  These classifications are completely customizable and can be used for just about any purpose, even non-security related ones.

Custom classifications can be created by the email administrators and distributed to end users for use within Outlook.  These could include message classifications such as “Confidential” and “Public” to convey the level of security associated with the email content.

One of two approaches could then be taken to enforce their usage.

1. Have email messages created with the most confidential classification by default, requiring the end user to deliberately lower the classification to send external emails.
2. Have email messages created with no classification by default, and require users to choose at least one before sending.

Message classifications can be used in conjunction with Transport Rules for enforcement.  For the two examples above Transport Rules could be created to:

1. Reject messages sent to external recipients that are classified as “Confidential”
2. Reject messages that are sent to external recipients with no classification set

Protecting Customer Information

Another use of Transport Rules is to assess emails based on their content.  If certain text patterns are found within an email message the Transport Rule can reject the message from being sent to an external recipient.

This is useful for organizations where email might be inadvertently used to transmit a credit card number or social security number, such as through human error or a system bug that failed to strip it out of an automatic message like an invoice.

Moderating Sensitive Mailboxes

The third option is to use moderation rules on sensitive mailboxes if certain conditions are met.  Again this makes use of Transport Rules which can send messages that are addressed to or from specified recipients to a moderation queue for approval.

One example of this would be a group of scientists working on confidential R&D under a specific manager.  The Transport Rule can send all emails from senders who have that manager to a moderation queue where the manager can check them for sensitive content.

Combinations of these three options could also be used.  For example, all staff under the R&D Manager that send messages to external recipients get moderated by the manager.

In summary, when sensitive information leaks are a risk and those scenarios can be clearly identified it is possible to make use of Exchange Server 2010 to reduce those risks.