CVE-2023-50387

Description

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-770 CWE-770

Affected Products

Vendor	Product	Versions
redhat	enterprise_linux	All
redhat	enterprise_linux	All
redhat	enterprise_linux	All
redhat	enterprise_linux	All
microsoft	windows_server_2008	All
microsoft	windows_server_2012	All
microsoft	windows_server_2012	All
microsoft	windows_server_2016	All
microsoft	windows_server_2019	All
microsoft	windows_server_2022	All
microsoft	windows_server_2022_23h2	All
fedoraproject	fedora	All
thekelleys	dnsmasq	< 2.90
nic	knot_resolver	< 5.71
powerdns	recursor	4.8.0 — 4.8.6
powerdns	recursor	4.9.0 — 4.9.3
powerdns	recursor	5.0.0 — 5.0.2
isc	bind	9.0.0 — 9.16.46
isc	bind	9.18.0 — 9.18.22
isc	bind	9.19.0 — 9.19.20
nlnetlabs	unbound	< 1.19.1

References

Advisories & Patches

https://gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-50387 https://nlnetlabs.nl/news/2024/Feb/13/unbound-1.19.1-released/ https://www.theregister.com/2024/02/13/dnssec_vulnerability_internet/ https://gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-50387 https://nlnetlabs.nl/news/2024/Feb/13/unbound-1.19.1-released/ https://www.theregister.com/2024/02/13/dnssec_vulnerability_internet/

Other References

http://www.openwall.com/lists/oss-security/2024/02/16/2 http://www.openwall.com/lists/oss-security/2024/02/16/3 https://access.redhat.com/security/cve/CVE-2023-50387 https://bugzilla.suse.com/show_bug.cgi?id=1219823 https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2024-01.html https://kb.isc.org/docs/cve-2023-50387 https://lists.debian.org/debian-lts-announce/2024/02/msg00006.html https://lists.debian.org/debian-lts-announce/2024/05/msg00011.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6FV5O347JTX7P5OZA6NGO4MKTXRXMKOZ/ https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/

Frequently Asked Questions

What is CVE-2023-50387? +

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2023-50387? +

CVE-2023-50387 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2023-50387? +

CVE-2023-50387 affects products from fedoraproject, isc, microsoft, nic, nlnetlabs, powerdns, redhat, thekelleys, specifically: bind, dnsmasq, enterprise_linux, fedora, knot_resolver, recursor, unbound, windows_server_2008, windows_server_2012, windows_server_2016, windows_server_2019, windows_server_2022, windows_server_2022_23h2. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2023-50387? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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