The SMTP service's SMTP greeting must not provide version information.

From Red Hat Enterprise Linux 5 Security Technical Implementation Guide

Associated with IA controls: ECSC-1

Associated with: CCI-000366

SV-37505r1_rule The SMTP service's SMTP greeting must not provide version information.

Vulnerability discussion

The version of the SMTP service can be used by attackers to plan an attack based on vulnerabilities present in the specific version.

Check content

Fix text

Ensure sendmail or Postfix has been configured to mask the version information. Procedure for sendmail: Change the O SmtpGreetingMessage line in the /etc/mail/sendmail.cf file as noted below: O SmtpGreetingMessage=$j Sendmail $v/$Z; $b change it to: O SmtpGreetingMessage= Mail Server Ready ; $b for Postfix: Examine the "smtpd_banner" line of /etc/postfix/main.conf and remove any "$mail_version" entry on it or comment the entire "smtpd_banner" line to use the default value which does not display the version information.

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