Red Hat Security Advisory: bind security update

Important

BIND may accept incorrect child-zone NSEC3 records as valid, which could allow an attacker to forge authenticated NXDOMAIN responses.

CWE-345 - Insufficient Verification of Data Authenticity

A DNSSEC validating resolver that is under a random subdomain attack against a DNSSEC-signed zone can suffer from runaway memory usage. The attacker needs to be able to send queries faster than the resolver can perform validation. The increased memory usage can be orders of magnitude beyond the limit configured in the max-cache-size parameter

CWE-400 - Uncontrolled Resource Consumption

It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes named to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For this attack to have any effect, the resolver under attack must have set synth-from-dnssec yes; (which is the default).

CWE-345 - Insufficient Verification of Data Authenticity

If a provably insecure domain is covered by both an NSEC and NSEC3 record at the parent, and there exist an RRSIG for only one of these types, then BIND may exit unexpectedly with an assertion while validating this proof.

CWE-617 - Reachable Assertion

The BIND resolver accepts validly-signed NSEC records where the "Next Domain Name" field points outside the signer's zone.