Messaging Gateway 10.7.5 sends "Bad Message" alerts when URL modification is enabled

Products

• Messaging Gateway

Issue/Introduction

Following the update to Messaging Gateway (SMG) 10.7.5, the SMG systems begin sending admin alert messages from "bad-msg-monitor" with the subject "Bad message found":

Subject: Bad message found

        The Symantec Messaging Gateway has determined that one or
more email messages are destabilizing the filtering process.
These messages are listed below and have been placed into
the Bad Message queue.
You may view and act on these messages from the command line
with the mta-control bad-msg command set.
Refer to the Symantec Messaging Gateway Administration Guide
for more information about the mta-control command.

Time: Tue, 02 Nov 2021 21:17:10 -0700
Host: smg.lab.bcp
Instance: inbound
Queue-ID: 40/00-16096-5DC02816

Environment

Release : 10.7.5

Component : URL modification

Cause

A defect in SMG 10.7.5 is preventing messages with an empty Subject header or misidentified content encoding from being processed by the URL modification feature.

Resolution

Some instances of this issue are resolved in Messaging Gateway 10.8.0.

For Messaging Gateway version 10.7.5 please update to version 10.8.0 or apply patch 10.7.5-292 as follows:

1. Log into the admin command line via ssh or putty.
2. Run the patch list command to confirm that patch 10.7.5-292 is accessible.

   smg [10.7.5-4]> patch list
   ...
   sms-appliance-patch.x86_64            10.7.5-292             symrepo_smg_patches

3. Install patch 10.7.5-292 by running the patch -p 10.7.5-292 install command.

   smg [10.7.5-4]> patch -p 10.7.5-292 install​

Workaround

Messages with an empty Subject header can be exempted from URL modification processing by adding a clause to the URL modification content filtering policy similar to the entry below:

As with all changes to Content Filtering policies, any change should be carefully tested using a limited set of test users before applying the change to larger groups of end users.