The remote host is missing an update to the system as announced in the referenced advisory FreeBSD-SA-09:03.ntpd.asc
Upgrade your system to the appropriate stable release or security branch dated after the correction date https://secure1.securityspace.com/smysecure/catid.html?in=FreeBSD-SA-09:03.ntpd.asc
The ntpd daemon is an implementation of the Network Time Protocol (NTP) used to synchronize the time of a computer system to a reference time source. FreeBSD includes software from the OpenSSL Project. The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, full-featured Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library. The EVP_VerifyFinal() function from OpenSSL is used to determine if a digital signature is valid. When ntpd(8) is set to cryptographically authenticate NTP data it incorrectly checks the return value from EVP_VerifyFinal().