The SMTP services SMTP greeting must not provide version information.

From SOLARIS 10 SPARC SECURITY TECHNICAL IMPLEMENTATION GUIDE

Associated with IA controls: ECSC-1

Associated with: CCI-000366

SV-42310r1_rule The SMTP services 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

Check for the Sendmail version being displayed in the greeting. # telnet localhost 25 If a version number is displayed, this is a finding. If telnet is unavailable for testing, check the value of the SmtpGreetingMessage parameter in the sendmail.cf file. # grep SmtpGreetingMessage /etc/mail/sendmail.cf If the value of the SmtpGreetingMessage parameter contains the $v or $Z macros, this is a finding.

Fix text

Ensure Sendmail or its equivalent has been configured to mask the version information. If necessary, 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

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.