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RHEL 5 : dnsmasq (Unpatched Vulnerability)

low Nessus Plugin ID 196874

Synopsis

The remote Red Hat 5 host is affected by multiple vulnerabilities that will not be patched.

Description

The remote Redhat Enterprise Linux 5 host has one or more packages installed that are affected by multiple vulnerabilities that have been acknowledged by the vendor but will not be patched.

 - dnsmasq: multiple queries forwarded for the same name makes forging replies easier for an off-path attacker (CVE-2020-25686)

 - A vulnerability was found in dnsmasq before version 2.81, where the memory leak allows remote attackers to cause a denial of service (memory consumption) via vectors involving DHCP response creation.
 (CVE-2019-14834)

 - A flaw was found in the default configuration of dnsmasq, as shipped with Fedora versions prior to 31 and in all versions Red Hat Enterprise Linux, where it listens on any interface and accepts queries from addresses outside of its local subnet. In particular, the option `local-service` is not enabled. Running dnsmasq in this manner may inadvertently make it an open resolver accessible from any address on the internet. This flaw allows an attacker to conduct a Distributed Denial of Service (DDoS) against other systems. (CVE-2020-14312)

 - A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity. (CVE-2020-25684)

 - A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1 when it is) this flaw allows an off-path attacker to find several different domains all having the same hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced.
 The highest threat from this vulnerability is to data integrity. (CVE-2020-25685)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package is installed.

Solution

The vendor has acknowledged the vulnerabilities but no solution has been provided. Refer to the vendor for remediation guidance.

Plugin Details

Severity: Low

ID: 196874

File Name: redhat_unpatched-dnsmasq-rhel5.nasl

Version: 1.1

Type: local

Agent: unix

Published: 5/11/2024

Updated: 5/11/2024

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

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 4.3

Temporal Score: 3.2

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

CVSS Score Source: CVE-2020-25686

CVSS v3

Risk Factor: Low

Base Score: 3.7

Temporal Score: 3.2

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

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

Vulnerability Information

CPE: cpe:/o:redhat:enterprise_linux:5, cpe:/o:redhat:enterprise_linux:6, p-cpe:/a:redhat:enterprise_linux:dnsmasq

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

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 1/7/2020

Reference Information

CVE: CVE-2019-14834, CVE-2020-14312, CVE-2020-25684, CVE-2020-25685, CVE-2020-25686