The Federal Rules of Civil Procedure (which most states have adopted in one form or another), state in effect that it is not necessary to file an answer to a complaint until a motion to dismiss has been ruled upon by the court. One way to begin arguing against the plaintiffs foreclosure action without filing an answer addressing the entire complaint is to file a motion to dismiss based on the plaintiffs inability to bring the lawsuit in the first place. Defendants can state that the plaintiff has not shown it even owns the mortgage and therefore has no claim to any of the defendant borrower's property. If the plaintiff does not have a right to collect the mortgage payments and foreclose, it is not the party in interest and may not legally bring a foreclosure lawsuit against the owner.
If the mortgage or note with assignment proof is not attached to the complaint, the plaintiff may have trouble showing it is legally allowed to foreclose on the subject property. Simply filing a copy of the original mortgage or deed of trust may not suffice. Some courts have held that the plaintiff must produce evidence that it is the current owner and assignee of the original note and mortgage.
No matter what defenses are set forth in the motion to dismiss, defendants need to be aware that this tactic only puts the foreclosure on hold until the motion can be ruled upon. It does not stop foreclosure entirely, and the defendant will need to file an answer if the motion is denied.