ID

VAR-202101-0221

CVE

CVE-2020-25685

TITLE

dnsmasq  Security check vulnerability in

DESCRIPTION

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. dnsmasq There is a security check vulnerability in.Information may be tampered with. Dnsmasq is a lightweight DNS forwarding and DHCP and TFTP server written in C language. Dnsmasq has a security vulnerability, which stems from the use of a weak hash algorithm (CRC32) to verify DNS responses when compiling without dnnssec. No detailed vulnerability details are currently provided. ========================================================================== Ubuntu Security Notice USN-4698-2 February 24, 2021 dnsmasq regression ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 20.10 - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS - Ubuntu 16.04 LTS Summary: USN-4698-1 introduced regressions in Dnsmasq. Software Description: - dnsmasq: Small caching DNS proxy and DHCP/TFTP server Details: USN-4698-1 fixed vulnerabilities in Dnsmasq. The updates introduced regressions in certain environments related to issues with multiple queries, and issues with retries. Original advisory details: Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled memory when sorting RRsets. A remote attacker could use this issue to cause Dnsmasq to hang, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-25681, CVE-2020-25687) Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled extracting certain names. A remote attacker could use this issue to cause Dnsmasq to hang, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-25682, CVE-2020-25683) Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly implemented address/port checks. (CVE-2020-25684) Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly implemented query resource name checks. (CVE-2020-25685) Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled multiple query requests for the same resource name. (CVE-2020-25686) It was discovered that Dnsmasq incorrectly handled memory during DHCP response creation. A remote attacker could possibly use this issue to cause Dnsmasq to consume resources, leading to a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2019-14834) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 20.10: dnsmasq 2.82-1ubuntu1.2 dnsmasq-base 2.82-1ubuntu1.2 dnsmasq-utils 2.82-1ubuntu1.2 Ubuntu 20.04 LTS: dnsmasq 2.80-1.1ubuntu1.3 dnsmasq-base 2.80-1.1ubuntu1.3 dnsmasq-utils 2.80-1.1ubuntu1.3 Ubuntu 18.04 LTS: dnsmasq 2.79-1ubuntu0.3 dnsmasq-base 2.79-1ubuntu0.3 dnsmasq-utils 2.79-1ubuntu0.3 Ubuntu 16.04 LTS: dnsmasq 2.75-1ubuntu0.16.04.8 dnsmasq-base 2.75-1ubuntu0.16.04.8 dnsmasq-utils 2.75-1ubuntu0.16.04.8 After a standard system update you need to reboot your computer to make all the necessary changes. Relevant releases/architectures: RHEL 8-based RHEV-H for RHEV 4 (build requirements) - noarch, x86_64 Red Hat Virtualization 4 Hypervisor for RHEL 8 - noarch, x86_64 Red Hat Virtualization 4 Management Agent for RHEL 7 Hosts - noarch 3. These packages include redhat-release-virtualization-host, ovirt-node, and rhev-hypervisor. RHVH features a Cockpit user interface for monitoring the host's resources and performing administrative tasks. Bug Fix(es): * Previously, the Red Hat Virtualization Host (RHV-H) repository (rhvh-4-for-rhel-8-x86_64-rpms) did not include the libsmbclient package, which is a dependency for the sssd-ad package. Consequently, the sssd-ad package failed to install. With this update, the libsmbclient is now in the RHV-H repository, and sssd-ad now installs on RHV-H. (BZ#1868967) 4. 7.2) - x86_64 3. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 ==================================================================== Red Hat Security Advisory Synopsis: Moderate: dnsmasq security update Advisory ID: RHSA-2021:0155-01 Product: Red Hat Enterprise Linux Advisory URL: https://access.redhat.com/errata/RHSA-2021:0155 Issue date: 2021-01-19 CVE Names: CVE-2020-25684 CVE-2020-25685 CVE-2020-25686 ==================================================================== 1. Summary: An update for dnsmasq is now available for Red Hat Enterprise Linux 7.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. 2. Relevant releases/architectures: Red Hat Enterprise Linux ComputeNode EUS (v. 7.6) - x86_64 Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.6) - x86_64 Red Hat Enterprise Linux Server EUS (v. 7.6) - ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Server Optional EUS (v. 7.6) - ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) - aarch64, ppc64le, s390x Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) - aarch64, ppc64le, s390x 3. Security Fix(es): * dnsmasq: loose address/port check in reply_query() makes forging replies easier for an off-path attacker (CVE-2020-25684) * dnsmasq: loose query name check in reply_query() makes forging replies easier for an off-path attacker (CVE-2020-25685) * dnsmasq: multiple queries forwarded for the same name makes forging replies easier for an off-path attacker (CVE-2020-25686) 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. 4. Solution: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 5. Bugs fixed (https://bugzilla.redhat.com/): 1889686 - CVE-2020-25684 dnsmasq: loose address/port check in reply_query() makes forging replies easier for an off-path attacker 1889688 - CVE-2020-25685 dnsmasq: loose query name check in reply_query() makes forging replies easier for an off-path attacker 1890125 - CVE-2020-25686 dnsmasq: multiple queries forwarded for the same name makes forging replies easier for an off-path attacker 6. Package List: Red Hat Enterprise Linux ComputeNode EUS (v. 7.6): Source: dnsmasq-2.76-7.el7_6.2.src.rpm x86_64: dnsmasq-2.76-7.el7_6.2.x86_64.rpm dnsmasq-debuginfo-2.76-7.el7_6.2.x86_64.rpm Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.6): x86_64: dnsmasq-debuginfo-2.76-7.el7_6.2.x86_64.rpm dnsmasq-utils-2.76-7.el7_6.2.x86_64.rpm Red Hat Enterprise Linux Server EUS (v. 7.6): Source: dnsmasq-2.76-7.el7_6.2.src.rpm ppc64: dnsmasq-2.76-7.el7_6.2.ppc64.rpm dnsmasq-debuginfo-2.76-7.el7_6.2.ppc64.rpm ppc64le: dnsmasq-2.76-7.el7_6.2.ppc64le.rpm dnsmasq-debuginfo-2.76-7.el7_6.2.ppc64le.rpm s390x: dnsmasq-2.76-7.el7_6.2.s390x.rpm dnsmasq-debuginfo-2.76-7.el7_6.2.s390x.rpm x86_64: dnsmasq-2.76-7.el7_6.2.x86_64.rpm dnsmasq-debuginfo-2.76-7.el7_6.2.x86_64.rpm Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7): Source: dnsmasq-2.76-7.el7_6.2.src.rpm aarch64: dnsmasq-2.76-7.el7_6.2.aarch64.rpm dnsmasq-debuginfo-2.76-7.el7_6.2.aarch64.rpm ppc64le: dnsmasq-2.76-7.el7_6.2.ppc64le.rpm dnsmasq-debuginfo-2.76-7.el7_6.2.ppc64le.rpm s390x: dnsmasq-2.76-7.el7_6.2.s390x.rpm dnsmasq-debuginfo-2.76-7.el7_6.2.s390x.rpm Red Hat Enterprise Linux Server Optional EUS (v. 7.6): ppc64: dnsmasq-debuginfo-2.76-7.el7_6.2.ppc64.rpm dnsmasq-utils-2.76-7.el7_6.2.ppc64.rpm ppc64le: dnsmasq-debuginfo-2.76-7.el7_6.2.ppc64le.rpm dnsmasq-utils-2.76-7.el7_6.2.ppc64le.rpm s390x: dnsmasq-debuginfo-2.76-7.el7_6.2.s390x.rpm dnsmasq-utils-2.76-7.el7_6.2.s390x.rpm x86_64: dnsmasq-debuginfo-2.76-7.el7_6.2.x86_64.rpm dnsmasq-utils-2.76-7.el7_6.2.x86_64.rpm Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7): aarch64: dnsmasq-debuginfo-2.76-7.el7_6.2.aarch64.rpm dnsmasq-utils-2.76-7.el7_6.2.aarch64.rpm ppc64le: dnsmasq-debuginfo-2.76-7.el7_6.2.ppc64le.rpm dnsmasq-utils-2.76-7.el7_6.2.ppc64le.rpm s390x: dnsmasq-debuginfo-2.76-7.el7_6.2.s390x.rpm dnsmasq-utils-2.76-7.el7_6.2.s390x.rpm These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from https://access.redhat.com/security/team/key/ 7. References: https://access.redhat.com/security/cve/CVE-2020-25684 https://access.redhat.com/security/cve/CVE-2020-25685 https://access.redhat.com/security/cve/CVE-2020-25686 https://access.redhat.com/security/updates/classification/#moderate https://access.redhat.com/security/vulnerabilities/RHSB-2021-001 8. Contact: The Red Hat security contact is <secalert@redhat.com>. More contact details at https://access.redhat.com/security/team/contact/ Copyright 2021 Red Hat, Inc. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIVAwUBYAboDtzjgjWX9erEAQiLag//YhXcBUOW0sEQ8k06WYSM8OkrXPNB0+Uq 53L0qcvoOWtSIkwV1CgVsHuLTXRPyelw4l/I3hZED+ACfEOUzGqYJOoWnc2HT712 e6rf5x8NVQpWpGLJbePFasiZ4b9Oe2cbpeveWUnJJyJ+9A/SKsAeANvvzvFIvPah le699qONS1DpTqS5v1vU7qqN0ZcdEdC83CeRjeYOoFx1+a9izFg9eKPyr3RdsrjF ze9Dv+6ZeCorrwMa9fyEVtmT91vmOGy6/1f2/9YlI9j/tjDfhv4HdlbHL0u2Eg2z eBaAkitgzgZ46L63hm6fNmTs9cO1AW+c8STkFjcv44vz4MJEQ60K2NiOqvuhm7ba GgU0rAJD1cPnHrriJ4DytwDpgGOhoC2a637mt0onni0U6ZZmvcVIkVY1m7muCyVr Vry4ViX/LrBgw+C46NTKHIlgZm2IzVH/OkgLpvXmf+SoQqQoiI75QaeTe432X9ie Ot9z14n5OFOwcAvOwnzUUIAR3oOxQfyhby8tgN+bRsIFOmYceYkocwc7DWGJQ+Zk mInUwGaEVAPkZzmTgxTjc5BGFdb9Ojsl32g1KbLAUv4SaUZtYzwGUxh0sMwEG5eY 8JqCsJP+4BDFBd70g7KZDdUkySJ0v3gb5+PS7KqnnRtYJb81Dl6FBxNc7x9KL8cG 3tTxc1zVYbM=RW1Z -----END PGP SIGNATURE----- -- RHSA-announce mailing list RHSA-announce@redhat.com https://www.redhat.com/mailman/listinfo/rhsa-announce . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Gentoo Linux Security Advisory GLSA 202101-17 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - https://security.gentoo.org/ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Severity: Normal Title: Dnsmasq: Multiple vulnerabilities Date: January 22, 2021 Bugs: #766126 ID: 202101-17 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Synopsis ======== Multiple vulnerabilities have been found in Dnsmasq, the worst of which may allow remote attackers to execute arbitrary code. Affected packages ================= ------------------------------------------------------------------- Package / Vulnerable / Unaffected ------------------------------------------------------------------- 1 net-dns/dnsmasq < 2.83 >= 2.83 Description =========== Multiple vulnerabilities have been discovered in Dnsmasq. Workaround ========== There is no known workaround at this time. Resolution ========== All Dnsmasq users should upgrade to the latest version: # emerge --sync # emerge --ask --oneshot --verbose ">=net-dns/dnsmasq-2.83" References ========== [ 1 ] CVE-2020-25681 https://nvd.nist.gov/vuln/detail/CVE-2020-25681 [ 2 ] CVE-2020-25682 https://nvd.nist.gov/vuln/detail/CVE-2020-25682 [ 3 ] CVE-2020-25683 https://nvd.nist.gov/vuln/detail/CVE-2020-25683 [ 4 ] CVE-2020-25684 https://nvd.nist.gov/vuln/detail/CVE-2020-25684 [ 5 ] CVE-2020-25685 https://nvd.nist.gov/vuln/detail/CVE-2020-25685 [ 6 ] CVE-2020-25686 https://nvd.nist.gov/vuln/detail/CVE-2020-25686 [ 7 ] CVE-2020-25687 https://nvd.nist.gov/vuln/detail/CVE-2020-25687 Availability ============ This GLSA and any updates to it are available for viewing at the Gentoo Security Website: https://security.gentoo.org/glsa/202101-17 Concerns? ========= Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users' machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org. License ======= Copyright 2021 Gentoo Foundation, Inc; referenced text belongs to its owner(s). The contents of this document are licensed under the Creative Commons - Attribution / Share Alike license. https://creativecommons.org/licenses/by-sa/2.5

IOT TAXONOMY

AFFECTED PRODUCTS

CVSS

PROBLEMTYPE DATA

THREAT TYPE

remote

TYPE

encryption problem

PATCH

EXTERNAL IDS

REFERENCES

CREDITS

Ubuntu

SOURCES

LAST UPDATE DATE

2026-02-07T21:52:24.120000+00:00

SOURCES UPDATE DATE

SOURCES RELEASE DATE