The SMTP service HELP command must not be enabled.

From SUSE Linux Enterprise Server v11 for System z Security Technical Implementation Guide

Associated with: CCI-000366

SV-45863r2_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 the sendmail package is installed: # rpm –q sendmail If sendmail is not installed, this check is not applicable. Check if Help is disabled. This rule is for “sendmail” only and not applicable to “Postfix”. Procedure: # telnet 25 > help If the help command returns any sendmail version information, this is a finding.

Fix text

To disable the SMTP HELP command, remove, rename or empty the /usr/lib/sendmail.d.helpfile file. # echo > /usr/lib/sendmail.d/helpfile

Pro Tips

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