How to filter a "Subject" bounded by asterisks

[dayooper]

I have been trying to create a filter to stop spam messages, but have been unsuccessful. All the spam messages are coming from different domains, but all of the subject lines are bounded by asterisks.

I have tried to do something like
Subject
Starts With
\*.*\*

Subject
Contains
^\*.*\*

But nothing work

Putting
Subject
Starts With
*
blocks everything