Whether property of a taxable person can be provisionally attached to protect the revenue

Yes. During the pendency of any proceedings under section 62, 63, 64, 67, 73 or 74, the Commissioner shall pass an order in Form GST DRC-22 to attach any property including bank account belonging to a taxable person provisionally for the purpose of protecting the interest of the Government revenue.

(ICAI FAQ PUBLICATIONS 06-09-2017 Provisional attachment to protect the revenue in certain cases : FAQ NO. 55)