RHEL 7 : unbound (RHSA-2015:2455)

Medium Nessus Plugin ID 86991

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VPR Score: 3.6


The remote Red Hat host is missing one or more security updates.


Updated unbound packages that fix one security issue and several bugs are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Low security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section.

The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.

A denial of service flaw was found in unbound that an attacker could use to trick the unbound resolver into following an endless loop of delegations, consuming an excessive amount of resources.

This update also fixes the following bugs :

* Prior to this update, there was a mistake in the time configuration in the cron job invoking unbound-anchor to update the root zone key.
Consequently, unbound-anchor was invoked once a month instead of every day, thus not complying with RFC 5011. The cron job has been replaced with a systemd timer unit that is invoked on a daily basis. Now, the root zone key validity is checked daily at a random time within a 24-hour window, and compliance with RFC 5011 is ensured. (BZ#1180267)

* Previously, the unbound packages were installing their configuration file for the systemd-tmpfiles utility into the /etc/tmpfiles.d/ directory. As a consequence, changes to unbound made by the administrator in /etc/tmpfiles.d/ could be overwritten on package reinstallation or update. To fix this bug, unbound has been amended to install the configuration file into the /usr/lib/tmpfiles.d/ directory. As a result, the system administrator's configuration in /etc/tmpfiles.d/ is preserved, including any changes, on package reinstallation or update. (BZ#1180995)

* The unbound server default configuration included validation of DNS records using the DNSSEC Look-aside Validation (DLV) registry. The Internet Systems Consortium (ISC) plans to deprecate the DLV registry service as no longer needed, and unbound could execute unnecessary steps. Therefore, the use of the DLV registry has been removed from the unbound server default configuration. Now, unbound does not try to perform DNS records validation using the DLV registry. (BZ#1223339)

All unbound users are advised to upgrade to these updated packages, which contain backported patches to correct these issues.


Update the affected packages.

See Also



Plugin Details

Severity: Medium

ID: 86991

File Name: redhat-RHSA-2015-2455.nasl

Version: 2.11

Type: local

Agent: unix

Published: 2015/11/20

Updated: 2019/10/24

Dependencies: 12634

Risk Information

Risk Factor: Medium

VPR Score: 3.6

CVSS v2.0

Base Score: 4.3

Temporal Score: 3.2

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P

Temporal Vector: CVSS2#E:U/RL:OF/RC:C

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:unbound, p-cpe:/a:redhat:enterprise_linux:unbound-debuginfo, p-cpe:/a:redhat:enterprise_linux:unbound-devel, p-cpe:/a:redhat:enterprise_linux:unbound-libs, p-cpe:/a:redhat:enterprise_linux:unbound-python, cpe:/o:redhat:enterprise_linux:7, cpe:/o:redhat:enterprise_linux:7.2, cpe:/o:redhat:enterprise_linux:7.3, cpe:/o:redhat:enterprise_linux:7.4, cpe:/o:redhat:enterprise_linux:7.5, cpe:/o:redhat:enterprise_linux:7.6, cpe:/o:redhat:enterprise_linux:7.7

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Available: false

Exploit Ease: No known exploits are available

Patch Publication Date: 2015/11/19

Vulnerability Publication Date: 2014/12/10

Reference Information

CVE: CVE-2014-8602

RHSA: 2015:2455