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HistoryJan 20, 2010 - 12:00 a.m.

(RHSA-2010:0062) Moderate: bind security update


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The Berkeley Internet Name Domain (BIND) is an implementation of the Domain
Name System (DNS) protocols. BIND includes a DNS server (named); a resolver
library (routines for applications to use when interfacing with DNS); and
tools for verifying that the DNS server is operating correctly.

A flaw was found in the BIND DNSSEC NSEC/NSEC3 validation code. If BIND was
running as a DNSSEC-validating resolver, it could incorrectly cache
NXDOMAIN responses, as if they were valid, for records proven by NSEC or
NSEC3 to exist. A remote attacker could use this flaw to cause a BIND
server to return the bogus, cached NXDOMAIN responses for valid records and
prevent users from retrieving those records (denial of service).

The original fix for CVE-2009-4022 was found to be incomplete. BIND was
incorrectly caching certain responses without performing proper DNSSEC
validation. CNAME and DNAME records could be cached, without proper DNSSEC
validation, when received from processing recursive client queries that
requested DNSSEC records but indicated that checking should be disabled. A
remote attacker could use this flaw to bypass the DNSSEC validation check
and perform a cache poisoning attack if the target BIND server was
receiving such client queries. (CVE-2010-0290)

All BIND users are advised to upgrade to these updated packages, which
contain a backported patch to resolve these issues. After installing the
update, the BIND daemon (named) will be restarted automatically.