Title

SMTP Virtual Servers do not Require Secure Channels and Encryption. (Cat II impact)

Discussion

The Simple Mail Transfer Protocol (SMTP) Virtual Server is used by the Exchange System Manager to send and receive messages from server to server using SMTP protocol. This setting controls the encryption strength used for client connections to the SMTP Virtual Server. With this feature enabled, only clients capable of supporting secure communications will be able to send mail using this SMTP server. Where secure channels are required, 128 bit encryption can also be selected. The use of secure communication prevents eavesdroppers from reading or modifying communications between mail clients and servers. While sensitive message bodies should be encrypted by the sender at the client, requiring a secure connection from the client to the server adds protection by encrypting the sender and recipient information that cannot be encrypted by the sender. Individually, channel security and encryption have been compromised by attackers. Used together, E-mail becomes a more difficult target, and security is heightened. Failure to enable this feature gives eavesdroppers an opportunity to read or modify messages between the client and server.

Check Content

Verify the SMTP virtual server connection security. Procedure: Exchange System Manager >> Administrative Groups >> [administrative group] >> servers >> [server] >> Protocols >> SMTP >> [specific SMTP virtual server] >> properties >> Access Tab >> Communication button “Require secure channel” and “Require 128 bit encryption” checkboxes should be checked. Criteria: If “Require secure channel” and “Require 128 bit encryption” are checked, this is not a finding.

Fix Text

For each SMTP virtual server, set secure connection as follows: Exchange System Manager >> Administrative Groups >> [administrative group] >> servers >> [server] >> Protocols >> SMTP >> [specific SMTP virtual server] >> properties >> Access Tab >> Communication button Select “Require secure channel” and “require 128 bit encryption” checkboxes.

Additional Identifiers

Rule ID: SV-20491r1_rule

Vulnerability ID: V-18782

Group Title:

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.