Verification of a recipient's email digital signature fails when using Kaspersky Security 8.0 for Linux Mail Server

Issue

Emails with digital signatures processed by Kaspersky Secure Mail Gateway may not pass the verification of the recipient.

Cause

The signature verification fails because of the X-KLMS-AntiVirus-Status header in the MIME part of the message.

Solution

Turn off adding titles to all parts of the email using the allowXHeadersForParts = 0 parameter and confirm adding general titles:

# /opt/kaspersky/klms/bin/klms-control --get-settings 3 | grep X

<addXHeaders>1</addXHeaders>

<allowXHeadersForParts>0</allowXHeadersForParts>

What to do if the issue persists

If the issue persists, submit a request to Kaspersky technical support via Kaspersky CompanyAccount. Please include a detailed description of the issue. Before contacting the support, see the guide on creating a request in the Knowledge Base.