You're on Medicare? For you, Oct. 15 to Dec. 7 means open enrollment. For scammers, it means prime time to try to steal your money and identity.

Although Medicare scams occur year-round, they dramatically spike in the weeks leading up to and through the annual window for participants to make changes to their health and prescription coverage.

So in coming weeks, remember the absolutely easiest step to avoid a Medicare scam: Never reveal your card number — it's the same as your Social Security number — or other personal health and financial information to anyone who's not a bona fide member of your health care team.

And keep an eye out for these dirtiest half-dozen open enrollment scams.

1. New card cons. In phone calls and occasionally emails or front-door visits, you're told that Medicare is issuing new cards, and to get yours, you need to provide identifying information such as your Medicare number, birth date or even financial account numbers. Identity theft is the real goal.

What to know: Medicare isn't issuing new cards and its employees don't contact participants through unsolicited calls, emails or visits. They won't ask for personal identifiers unless you contact the agency yourself.

2. Refund rip-offs. Scammers claim you're entitled to money back because of "changes" or "enhancements" by Medicare or private insurers, or because of purported lawsuits or actions by government agencies. In these schemes, the goal is to get not only your Medicare number, but your bank account information for a supposed direct deposit.

What to know: If you're really entitled to a refund, a check will be sent directly to you. You won't have to "prove" or provide anything. If you get Social Security, Uncle Sam already has your direct-deposit account on file, so Medicare wouldn't ask for it.

Open enrollment for Medicare is prime time for scammers. — Corbis

3. Posers galore. In seeking your personal information, crooks may also claim to be from state or local health agencies, doctor's offices or hospitals, or an official-sounding but phony organization such as the National Medical Office. And they may try to trick you by manipulating your caller ID screen.

What to know: Never trust caller ID. Scammers can easily make it display whatever identity and phone number they choose, thanks to "spoofing" products for sale on the Internet. Also, don't be taken in if callers have personal info about you: Fraudsters have been known to contact Medicare patients and accurately give the names and addresses of their doctors. It's unclear how they got the information.

If you think a call may be genuine, hang up, look up the agency's number yourself and call it back. For Medicare, it's 800-633-4227 (for TTY callers, dial 877-486-2048 toll-free).

Next: Watch out for unsolicited calls offering free stuff. »