bind9 regression

USN-3346-1 fixed vulnerabilities in Bind. The fix for CVE-2017-3142
introduced a regression in the ability to receive an AXFR or IXFR in the
case where TSIG is used and not every message is signed. This update fixes
the problem.

In addition, this update adds the new root zone key signing key (KSK).

Original advisory details:

Clément Berthaux discovered that Bind did not correctly check TSIG
authentication for zone update requests. An attacker could use this
to improperly perform zone updates. (CVE-2017-3143)

Clément Berthaux discovered that Bind did not correctly check TSIG
authentication for zone transfer requests. An attacker could use this
to improperly transfer entire zones. (CVE-2017-3142)