RHEL 8 : unbound (RHSA-2024:2696)

high Nessus Plugin ID 194993

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Synopsis

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

Description

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2024:2696 advisory.

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

Security Fix(es):

* bind9: KeyTrap - Extreme CPU consumption in DNSSEC validator (CVE-2023-50387)

* bind9: Preparing an NSEC3 closest encloser proof can exhaust CPU resources (CVE-2023-50868)

* A vulnerability was found in Unbound due to incorrect default permissions, allowing any process outside the unbound group to modify the unbound runtime configuration. The default combination of the control- use-cert: no option with either explicit or implicit use of an IP address in the control-interface option could allow improper access. If a process can connect over localhost to port 8953, it can alter the configuration of unbound.service. This flaw allows an unprivileged local process to manipulate a running instance, potentially altering forwarders, allowing them to track all queries forwarded by the local resolver, and, in some cases, disrupting resolving altogether.

To mitigate the vulnerability, a new file /etc/unbound/conf.d/remote-control.conf has been added and included in the main unbound configuration file, unbound.conf. The file contains two directives that should limit access to unbound.conf:

control-interface: /run/unbound/control control-use-cert: yes

For details about these directives, run man unbound.conf.

Updating to the version of unbound provided by this advisory should, in most cases, address the vulnerability. To verify that your configuration is not vulnerable, use the unbound-control status | grep control command. If the output contains control(ssl) or control(namedpipe), your configuration is not vulnerable. If the command output returns only control, the configuration is vulnerable because it does not enforce access only to the unbound group members. To fix your configuration, add the line include:
/etc/unbound/conf.d/remote-control.conf to the end of the file /etc/unbound/unbound.conf. If you use a custom /etc/unbound/conf.d/remote-control.conf file, add the new directives to this file.
(CVE-2024-1488)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the RHEL unbound package based on the guidance in RHSA-2024:2696.

Plugin Details

Severity: High

ID: 194993

File Name: redhat-RHSA-2024-2696.nasl

Version: 1.3

Type: local

Agent: unix

Family: Red Hat Local Security Checks

Published: 5/6/2024

Updated: 11/8/2024

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.5

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2023-50387

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:unbound-libs, cpe:/o:redhat:rhel_aus:8.2, cpe:/o:redhat:rhel_tus:8.2, p-cpe:/a:redhat:enterprise_linux:unbound-devel, cpe:/o:redhat:rhel_e4s:8.2, p-cpe:/a:redhat:enterprise_linux:python3-unbound, p-cpe:/a:redhat:enterprise_linux:unbound

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/6/2024

Vulnerability Publication Date: 2/13/2024

Reference Information

CVE: CVE-2023-50387, CVE-2023-50868, CVE-2024-1488

CWE: 15, 400

RHSA: 2024:2696

Detections

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