The remote Debian host is missing a security-related update.
Jonathan Foote discovered that the BIND DNS server does not properly handle TKEY queries. A remote attacker can take advantage of this flaw to mount a denial of service via a specially crafted query triggering an assertion failure and causing BIND to exit.
Upgrade the bind9 packages. For the oldstable distribution (wheezy), this problem has been fixed in version 1:9.8.4.dfsg.P1-6+nmu2+deb7u6. For the stable distribution (jessie), this problem has been fixed in version 1:9.9.5.dfsg-9+deb8u2.