Title

The Mailbox server is not protected by having blank sender messages filtered by the Edge Transport Role server (E-mail Secure Gateway) at the perimeter. (Cat II impact)

Discussion

By performing filtering at the perimeter, up to 90% of SPAM, malware, and other undesirable messages are eliminated from the message stream rather than admitting them into the mail server environment. Anonymous E-mail (messages with blank sender fields) cannot be replied to. Messages formatted in this way may be attempting to hide their true origin to avoid responses, or to SPAM any receiver with impunity while hiding their source of origination. Rather than spend resource and risk infection while evaluating them, it is recommended that these messages be filtered immediately upon receipt and not forwarded to end users.

Check Content

Interview the E-mail Administrator or the IAO. Request documentation that indicates Messages with blank senders are filtered at the perimeter by an Edge Tranport Server role (E-mail Secure Gateway). Criteria: If inbound messages with blank sender are filtered and archived, this is not a finding.

Fix Text

Implement perimeter-based protection in the form of an Edge Transport Role server (E-mail Secure Gateway) filtering mechanism that performs, among other protections, filtering messages with blank sender and archiving them for SPAM elimination.

Additional Identifiers

Rule ID: SV-20292r1_rule

Vulnerability ID: V-18674

Group Title:

Expert Comments

CCIs tied to check.

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