XF 1.5 Trapping posts containing http in subject for moderation

Most of the spam posts we've been receiving lately have had subject lines containing full URLs beginning with http. Is there any way to trap these automatically and put them into the moderation queue?
Thanks for the amazingly quick response.

Does "spam phrases" work on subject lines?

To be sure we're on the same page I'm looking to trap URLs in the message subject line. At this point I'm not looking to trap in the body of the message if I can help it.

Would the suggested code do what I want?
Revisiting this topic. Spammers have learned that they can bypass this trap if they create a survey poll and hide the URL in there. Is there any way to trap URLs in surveys polls? Or, prevent surveys polls from accepting URLs in the first place?
Last edited: