The SMTP service HELP command must not be enabled.

From SOLARIS 10 SPARC SECURITY TECHNICAL IMPLEMENTATION GUIDE

Associated with IA controls: ECSC-1

Associated with: CCI-000366

SV-42309r1_rule The SMTP service HELP command must not be enabled.

Vulnerability discussion

The HELP command should be disabled to mask version information. The version of the SMTP service software could be used by attackers to target vulnerabilities present in specific software versions.

Check content

Check if Help is disabled in Sendmail. Procedure: # telnet 25 > help If the help command returns any Sendmail version information, this is a finding. If telnet is unavailable for testing, check the value of the HelpFile parameter in the sendmail.cf file. # grep HelpFile /etc/mail/sendmail.cf If the contents of the file indicated by the HelpFile parameter contains any Sendmail version information, this is a finding.

Fix text

To disable the SMTP HELP command, clear the Sendmail help file. # echo > /etc/mail/helpfile

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.