BIND: Denial of Service

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200908-02 / bind
Release Date	August 01, 2009
Latest Revision	August 01, 2009: 01
Impact	normal
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
net-dns/bind	< 9.4.3_p3	>= 9.4.3_p3	All supported architectures

Related bugreports: #279508

Synopsis

Dynamic Update packets can cause a Denial of Service in the BIND daemon.

2. Impact Information

Background

ISC BIND is the Internet Systems Consortium implementation of the Domain Name System (DNS) protocol.

Description

Matthias Urlichs reported that the dns_db_findrdataset() function fails when the prerequisite section of the dynamic update message contains a record of type "ANY" and where at least one RRset for this FQDN exists on the server.

Impact

A remote unauthenticated attacker could send a specially crafted dynamic update message to the BIND daemon (named), leading to a Denial of Service (daemon crash). This vulnerability affects all primary (master) servers -- it is not limited to those that are configured to allow dynamic updates.

3. Resolution Information

Workaround

Configure a firewall that performs Deep Packet Inspection to prevent nsupdate messages from reaching named. Alternatively, expose only secondary (slave) servers to untrusted networks.

Resolution

All BIND users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dns/bind-9.4.3_p3"

4. References

Updated August 01, 2009

Summary: This is a Gentoo Linux Security Advisory

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