GLSA-200708-13 : BIND: Weak random number generation

This script is Copyright (C) 2007-2014 Tenable Network Security, Inc.


Synopsis :

The remote Gentoo host is missing one or more security-related
patches.

Description :

The remote host is affected by the vulnerability described in GLSA-200708-13
(BIND: Weak random number generation)

Amit Klein from Trusteer reported that the random number generator of
ISC BIND leads, half the time, to predictable (1 chance to 8) query IDs
in the resolver routine or in zone transfer queries (CVE-2007-2926).
Additionally, the default configuration file has been strengthen with
respect to the allow-recursion{} and the allow-query{} options
(CVE-2007-2925).

Impact :

A remote attacker can use this weakness by sending queries for a domain
he handles to a resolver (directly to a recursive server, or through
another process like an email processing) and then observing the
resulting IDs of the iterative queries. The attacker will half the time
be able to guess the next query ID, then perform cache poisoning by
answering with those guessed IDs, while spoofing the UDP source address
of the reply. Furthermore, with empty allow-recursion{} and
allow-query{} options, the default configuration allowed anybody to
make recursive queries and query the cache.

Workaround :

There is no known workaround at this time for the random generator
weakness. The allow-recursion{} and allow-query{} options should be set
to trusted hosts only in /etc/bind/named.conf, thus preventing several
security risks.

See also :

http://www.gentoo.org/security/en/glsa/glsa-200708-13.xml

Solution :

All ISC BIND users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose '>=net-dns/bind-9.4.1_p1'

Risk factor :

Medium / CVSS Base Score : 5.8
(CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N)

Family: Gentoo Local Security Checks

Nessus Plugin ID: 25919 (gentoo_GLSA-200708-13.nasl)

Bugtraq ID:

CVE ID: CVE-2007-2925
CVE-2007-2926