FreeBSD Security Advisory – Testing by ISC has uncovered a defect in control channel input handling which can cause named to exit due to an assertion failure in sexpr.c or alist.c when a malformed packet is sent to named’s control channel (the interface which allows named to be controlled using the “rndc” server control utility). An error when parsing signature records for DNAME records having specific properties can lead to named exiting due to an assertion failure in resolver.c or db.c. A remote attacker can deliberately trigger the failed assertion if the DNS server accepts remote rndc commands regardless if authentication is configured. Note that this is not enabled by default. A remote attacker who can cause a server to make a query deliberately chosen to generate a response containing a signature record which would trigger a failed assertion and cause named to stop. Disabling DNSsec does not provide protection against this vulnerability.