Hi all,
not sure if this interesting but we have had a little similar discussion in → https://community.ipfire.org/t/protect-users-who-get-spammy-phishing-links-in-emails in here → Protect users who get spammy phishing links in emails - #40 by ummeegge (more specific) with an older idea of how to get lists updated in SquidGuard with a little bashing around but more important are IMHO some good lists.
Best,
Erik