CVE-2023-50387: Unbound: disclosure of CVE-2023-50387 and CVE-2023-50868 DNSSEC validation vulnerabilities
First published: Mon Feb 12 2024(Updated: )
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.
Credit: cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Microsoft Windows Server 2008 R2 | ||
| Microsoft Windows Server 2022 | ||
| Microsoft Windows Server 2012 R2 | ||
| Microsoft Windows Server 2022 | ||
| Microsoft Windows Server 2012 R2 | ||
| Microsoft Windows Server 2019 | ||
| Microsoft Windows Server 2008 R2 | ||
| Microsoft Windows Server 2016 | ||
| Microsoft Windows Server 2016 | ||
| Microsoft Windows Server 2019 | ||
| Microsoft Windows Server 2012 x64 | ||
| Microsoft Windows Server 2012 x64 | ||
| Microsoft Windows Server 2022 23H2 | ||
| debian/bind9 | 1:9.16.50-1~deb11u2 1:9.16.50-1~deb11u3 1:9.18.28-1~deb12u2 1:9.18.33-1~deb12u2 1:9.20.4-4 1:9.20.5-1 | |
| debian/dnsjava | <=2.1.8-2 | 3.6.2-2 |
| debian/dnsmasq | <=2.85-1 | 2.85-1+deb11u1 2.90-4~deb12u1 2.91~test9-1 |
| debian/knot-resolver | <=5.3.1-1+deb11u1 | 5.6.0-1+deb12u1 5.7.4-2 |
| debian/pdns-recursor | <=4.4.2-3 | 4.8.8-1 4.8.8-1+deb12u1 5.1.3-2 5.2.0-2 |
| debian/systemd | <=247.3-7+deb11u5 | 247.3-7+deb11u6 252.33-1~deb12u1 257.3-1 |
| debian/unbound | 1.13.1-1+deb11u2 1.13.1-1+deb11u4 1.17.1-2+deb12u2 1.22.0-1 | |
| F5 BIG-IP and BIG-IQ Centralized Management | >=17.1.0<=17.1.1 | 17.1.2 |
| F5 BIG-IP and BIG-IQ Centralized Management | >=16.1.0<=16.1.5 | |
| F5 BIG-IP and BIG-IQ Centralized Management | >=15.1.0<=15.1.10 | |
| redhat/bind | <9.16.48 | 9.16.48 |
| redhat/bind | <9.18.24 | 9.18.24 |
| redhat/bind | <9.19.21 | 9.19.21 |
| Red Hat Enterprise Linux | =6.0 | |
| Red Hat Enterprise Linux | =7.0 | |
| Red Hat Enterprise Linux | =8.0 | |
| Red Hat Enterprise Linux | =9.0 | |
| Microsoft Windows Server 2008 Itanium | =r2-sp1 | |
| Microsoft Windows Server 2012 x64 | ||
| Microsoft Windows Server 2012 x64 | =r2 | |
| Microsoft Windows Server 2016 | ||
| Microsoft Windows Server 2019 | ||
| Microsoft Windows Server 2022 | ||
| Microsoft Windows Server 2022 23H2 | ||
| Fedora | =39 | |
| dnsmasq | <2.90 | |
| nic knot resolver | <5.71 | |
| PowerDNS | >=4.8.0<4.8.6 | |
| PowerDNS | >=4.9.0<4.9.3 | |
| PowerDNS | >=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 | |
| libunbound | <1.19.1 |
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Reference Links
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-50387 (Advisory)
- https://www.theregister.com/2024/02/13/dnssec_vulnerability_internet/
- https://www.bleepingcomputer.com/news/security/keytrap-attack-internet-access-disrupted-with-one-dns-packet/
- https://www.theregister.com/2024/03/26/software_risk_scores/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PNNHZSZPG2E7NBMBNYPGHCFI4V4XRWNQ/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SVYA42BLXUCIDLD35YIJPJSHDIADNYMP/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RGS7JN6FZXUSTC2XKQHH27574XOULYYJ/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UQESRWMJCF4JEYJEAKLRM6CT55GLJAB7/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TEXGOYGW7DBS3N2QSSQONZ4ENIRQEAPG/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/
- 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://gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1
- https://kb.isc.org/docs/cve-2023-50387
- https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2024q1/017430.html
- https://news.ycombinator.com/item?id=39367411
- https://news.ycombinator.com/item?id=39372384
- https://nlnetlabs.nl/news/2024/Feb/13/unbound-1.19.1-released/
- https://www.athene-center.de/aktuelles/key-trap
- https://www.athene-center.de/fileadmin/content/PDF/Technical_Report_KeyTrap.pdf
- https://www.isc.org/blogs/2024-bind-security-release/
- https://www.securityweek.com/keytrap-dns-attack-could-disable-large-parts-of-internet-researchers/
- https://lists.debian.org/debian-lts-announce/2024/02/msg00006.html
- http://www.openwall.com/lists/oss-security/2024/02/16/2
- http://www.openwall.com/lists/oss-security/2024/02/16/3
- https://security.netapp.com/advisory/ntap-20240307-0007/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/6FV5O347JTX7P5OZA6NGO4MKTXRXMKOZ/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IGSLGKUAQTW5JPPZCMF5YPEYALLRUZZ6/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/
- https://lists.debian.org/debian-lts-announce/2024/05/msg00011.html
- https://launchpad.net/bugs/cve/CVE-2023-50387
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SVYA42BLXUCIDLD35YIJPJSHDIADNYMP/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PNNHZSZPG2E7NBMBNYPGHCFI4V4XRWNQ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TEXGOYGW7DBS3N2QSSQONZ4ENIRQEAPG/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UQESRWMJCF4JEYJEAKLRM6CT55GLJAB7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGS7JN6FZXUSTC2XKQHH27574XOULYYJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/
- 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/IGSLGKUAQTW5JPPZCMF5YPEYALLRUZZ6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-50387
- https://nvd.nist.gov/vuln/detail/CVE-2023-50387
- https://security-tracker.debian.org/tracker/CVE-2023-50387
- https://ubuntu.com/security/CVE-2023-50387
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2264067
- https://fosstodon.org/@tychotithonus@infosec.exchange/111924626751024210
- https://github.com/NLnetLabs/unbound/releases/tag/release-1.19.1
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2264103
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2264104
- https://www.athene-center.de/en/news/press/key-trap
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2264363
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2264397
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2264396
- https://www.knot-resolver.cz/2024-02-13-knot-resolver-5.7.1.html
- https://labs.ripe.net/author/haya-shulman/keytrap-algorithmic-complexity-attacks-exploit-fundamental-design-flaw-in-dnssec/
- https://lists.dns-oarc.net/pipermail/dns-operations/2024-February/022436.html
- https://access.redhat.com/errata/RHSA-2024:0965
- https://access.redhat.com/errata/RHSA-2024:0977
- https://access.redhat.com/errata/RHSA-2024:0981
- https://access.redhat.com/errata/RHSA-2024:0982
- https://access.redhat.com/errata/RHSA-2024:1334
- https://access.redhat.com/errata/RHSA-2024:1335
- https://access.redhat.com/errata/RHSA-2024:1522
- https://access.redhat.com/errata/RHSA-2024:1543
- https://access.redhat.com/errata/RHSA-2024:1544
- https://access.redhat.com/errata/RHSA-2024:1545
- https://access.redhat.com/errata/RHSA-2024:1647
- https://access.redhat.com/errata/RHSA-2024:1648
- https://access.redhat.com/errata/RHSA-2024:1781
- https://access.redhat.com/errata/RHSA-2024:1782
- https://access.redhat.com/errata/RHSA-2024:1789
- https://access.redhat.com/errata/RHSA-2024:1801
- https://access.redhat.com/errata/RHSA-2024:1800
- https://access.redhat.com/errata/RHSA-2024:1804
- https://access.redhat.com/errata/RHSA-2024:1803
- https://access.redhat.com/errata/RHSA-2024:2551
- https://access.redhat.com/errata/RHSA-2024:2587
- https://access.redhat.com/errata/RHSA-2024:2696
- https://access.redhat.com/errata/RHSA-2024:2720
- https://access.redhat.com/errata/RHSA-2024:2721
- https://access.redhat.com/errata/RHSA-2024:2821
- https://access.redhat.com/errata/RHSA-2024:2890
- https://access.redhat.com/errata/RHSA-2024:3271
- https://access.redhat.com/errata/RHSA-2024:3741
- https://access.redhat.com/errata/RHSA-2024:3877
- https://access.redhat.com/errata/RHSA-2024:3929
- https://access.redhat.com/errata/RHSA-2024:11003
- https://access.redhat.com/errata/RHSA-2025:0039
- https://bugzilla.redhat.com/show_bug.cgi?id=2263914
- https://my.f5.com/manage/s/article/K000139092
- https://gitlab.isc.org/isc-projects/bind9/-/commit/c12608ca934c0433d280e65fe6c631013e200cfe
- https://gitlab.isc.org/isc-projects/bind9/-/commit/751b7cc4750ede6d8c5232751d60aad8ad84aa67
- https://gitlab.isc.org/isc-projects/bind9/-/commit/6a65a425283d70da86bf732449acd6d7c8dec718
- https://gitlab.isc.org/isc-projects/bind9/-/commit/3d206e918b3efbc20074629ad9d99095fbd2e5fd
- https://gitlab.isc.org/isc-projects/bind9/-/commit/a520fbc0470a0d6b72db6aa0b8deda8798551614
- https://downloads.isc.org/isc/bind9/9.16.48/patches/0005-CVE-2023-50387-CVE-2023-50868.patch
- https://github.com/CZ-NIC/knot-resolver/commit/7ddabe80fa05b76fc57b5a112a82a2c032032534
- https://github.com/CZ-NIC/knot-resolver/commit/feb65eb97b93f0f024d70c7f5f6cbc6802ba02ec
- https://github.com/CZ-NIC/knot-resolver/commit/cc5051b4441307d9b262fa382bc715391112ddbb
- https://blog.powerdns.com/2024/02/13/powerdns-recursor-4-8-6-4-9-3-5-0-2-released
- https://github.com/PowerDNS/pdns/pull/13781
- https://nlnetlabs.nl/downloads/unbound/CVE-2023-50387_CVE-2023-50868.txt
- https://github.com/NLnetLabs/unbound/commit/882903f2fa800c4cb6f5e225b728e2887bb7b9ae
- https://github.com/systemd/systemd/issues/31413
- https://github.com/systemd/systemd/commit/67d0ce8843d612a2245d0966197d4f528b911b66
- https://github.com/systemd/systemd/commit/eba291124bc11f03732d1fc468db3bfac069f9cb
- https://github.com/systemd/systemd-stable/commit/1ebdb19ff194120109b08bbf888bdcc502f83211
- https://github.com/systemd/systemd-stable/commit/572692f0bdd6a3fabe3dd4a3e8e5565cc69b5e14
- https://github.com/systemd/systemd-stable/commit/2f5edffa8ffd5210165ebe7604f07d23f375fe9a
- https://github.com/systemd/systemd-stable/commit/9899281c59a91f19c8b39362d203e997d2faf233
- https://github.com/systemd/systemd-stable/commit/7886eea2425fe7773cc012da0b2e266e33d4be12
- https://github.com/systemd/systemd-stable/commit/156e519d990a5662c719a1cbe80c6a02a2b9115f
- https://github.com/systemd/systemd-stable/commit/7633d969f3422f9ad380a512987d398e54764817
- https://github.com/systemd/systemd-stable/commit/b43bcb51ebf9aea21b1e280e1872056994e3f53d
- https://github.com/advisories/GHSA-crjg-w57m-rqqf
- https://github.com/dnsjava/dnsjava/commit/07ac36a11578cc1bce0cd8ddf2fe568f062aee78
- https://github.com/dnsjava/dnsjava/commit/3ddc45ce8cdb5c2274e10b7401416f497694e1cf
- https://www.ibm.com/support/pages/node/7182403 (Advisory)
Frequently Asked Questions
What is the severity of CVE-2023-50387?
CVE-2023-50387 has been assessed with a severity level that allows remote attackers to cause a denial of service.
What systems are affected by CVE-2023-50387?
CVE-2023-50387 affects multiple versions of Microsoft Windows Server, various DNS software including BIND and PowerDNS, and several Linux distributions.
How do I fix CVE-2023-50387?
To fix CVE-2023-50387, apply the specific patches and updates provided by your software vendor.
What is the nature of the vulnerability in CVE-2023-50387?
The vulnerability in CVE-2023-50387 originates from certain DNSSEC aspects of the DNS protocol that can be exploited for denial of service.
Are there any workarounds for CVE-2023-50387?
While updating is highly recommended, temporary network configurations to limit DNS response processing might serve as a workaround for CVE-2023-50387.
- collector/oss-sec
- source/oss-sec
- alias/CVE-2023-50387
- alias/CVE-2023-50868
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- alias/CVE-2023-6516
- collector/msrc
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- canonical/libunbound