Problems with Sift Workstation on Qubes OS 4.0

For a while now, I have had issues with Sift Workstation in Qubes OS VM. You can read about my issue on the sift-cli github: teamdfir/sift#357

The sources.list file after I run the sift install/upgrade is as follows:

$ cat /etc/apt/sources.list
deb http://archive.ubuntu.com/ubuntu xenial universe
deb http://archive.canonical.com/ubuntu xenial partner
deb http://archive.ubuntu.com/ubuntu xenial-security multiverse
deb http://archive.ubuntu.com/ubuntu xenial-updates main universe multiverse restricted
deb http://qubes.3isec.org/4.0 xenial main
deb http://archive.ubuntu.com/ubuntu xenial multiverse

Notice the first line. It should be 'main universe' instead it happens to be just 'universe'. This is wrong and you will get failures.

For some reason, I did not consider usig a 'custom' repo file for this missing configuration. Created a new file located at: /etc/apt/sources.list.d/ubuntu-mail.list

It contained one line: deb http://archive.ubuntu.com/ubuntu xenial main

Then, I ran the sift update command again with everything working as intended.