The rise of highly targeted spam emails

[Sebastian Arcus]

I have noticed in the last half a year or so the rise in much more 
focused email campaigns. I have some solicitor and accountant clients 
who receive these scam emails which are a notch above the rest. The 
English is good and correctly spelled. The footers look professional and 
just like the ones from other offices in the trade. The wording is very 
similar to the usual emails they receive - such as a reminders for 
payments, or an enquiry about documentation for the sale of a house. The 
emails often contain links to various popular cloud platforms - such as 
SharePoint, DropBox etc. Most of the emails come from clean domains, or 
from large webmail providers.

I can't really train the bayesian filter on these emails, as it would 
start to affect ham emails classification. I also assume that RBL's 
can't do much, as they would have to block everything from DropBox or 
SharePoint if they start blacklisting these emails.  Is there anything 
else that could be done to block this stuff? Have others seen these 
types of emails?