Depends on the endorsement. If someone writes it to you, then you are a "Holder in Due Course." Signed in blank (just the sig) then all someone needs to do is sign below your name and present identification to cash it at the issuing bank. That's called "Blank Endorsement" and makes the check a "Bearer Instrument," which anyone can sign and present for payment. You have no recourse toward the bank if someone steals it, signs it and cashes it. You would have to find the person that cashed it to get the money back, assuming they haven't fled the country.
Either (1) Don't sign it until you are ready to cash it (like it was mentioned before), or (2) put "for deposit only" on it and the account number. You don't even have to sign it. An unsigned check is easy to forge, but hard to cash without correct identification. For Deposit Only makes it a "Restricted Instrument" and the payor must honor the restriction. In other words, the bank can only deposit it as instructed by the Holder.
Don't ever assume that a check is traceable. There are many very good fake identification cards out there. The bank I work for has resorted to having people put a fingerprint on the check to help prevent forgery. It doesn't prevent all of them and many banks don't do that. A professional will find a way to cash a check if they want the money bad enough. Most of them are never found.