Most spam messages sent in recent days have been delivered with subject lines containing fake order or ticket numbers, delivery invoices, payment notices or tax information, according to researchers from security firm Websense. The top campaign contains subject lines such as “Order N21560," Artem Gololobov, security researcher at Websense, said in a blog post Thursday. The messages direct users to click on a link where they can supposedly download a license for the Adobe CS4 website design software. The link, however, actually leads users to the Blackhole exploit kit. Other prevalent spam campaigns leading to this exploit contain subject lines displaying phony traffic ticket or flight order numbers.