CVE-2023-50387: Unbound: disclosure of CVE-2023-50387 and CVE-2023-50868 DNSSEC validation vulnerabilities

Published 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.

Other sources

ISC BIND is vulnerable to a denial of service, caused by an error when processing responses coming from specially crafted DNSSEC-signed zones. By flooding the target server with queries, a remote attacker could exploit this vulnerability to cause CPU exhaustion on a DNSSEC-validating resolver.

— IBM

MITRE: CVE-2023-50387 DNSSEC verification complexity can be exploited to exhaust CPU resources and stall DNS resolvers

— Microsoft

The processing of responses coming from specially crafted DNSSEC-signed zones can cause CPU exhaustion on a DNSSEC-validating resolver.

— Red Hat

Affected Software

86 affected componentsFixes available
redhat/bind<9.16.48
9.16.48
redhat/bind<9.18.24
9.18.24
redhat/bind<9.19.21
9.19.21
F5 BIG-IP>=17.1.0<=17.1.1
17.1.2
F5 BIG-IP>=16.1.0<=16.1.6
16.1.6.1
F5 BIG-IP>=15.1.0<=15.1.10
15.1.10.8
redhat Enterprise Linux=6.0
redhat Enterprise Linux=7.0
redhat Enterprise Linux=8.0
redhat Enterprise Linux=9.0
Microsoft Windows Server 2008=r2-sp1
Microsoft Windows Server 2012
Microsoft Windows Server 2012=r2
Microsoft Windows Server 2016
Microsoft Windows Server 2019
Microsoft Windows Server 2022
Microsoft Windows Server 2022 23h2
Fedoraproject Fedora=39
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
Microsoft Windows Server 2012 R2<6.3.9600.21813
6.3.9600.21813
Microsoft Windows Server 2012<6.2.9200.24710
6.2.9200.24710
Microsoft Windows Server 2012<6.2.9200.24710
6.2.9200.24710
Microsoft Windows Server 2008 R2<6.1.7601.26961
6.1.7601.26961
Microsoft Windows Server 2008 R2<6.1.7601.26961
6.1.7601.26961
Microsoft Windows Server 2022<10.0.20348.2322
10.0.20348.2322
Microsoft Windows Server 2016<10.0.14393.6709
10.0.14393.6709
Microsoft Windows Server 2012 R2<6.3.9600.21813
6.3.9600.21813
Microsoft Windows Server 2016<10.0.14393.6709
10.0.14393.6709
Microsoft Windows Server 2022<10.0.20348.2322
10.0.20348.2322
Microsoft Windows Server 2019<10.0.17763.5458
10.0.17763.5458
Microsoft Windows Server 2022, 23H2 Edition<10.0.25398.709
10.0.25398.709
Microsoft Windows Server 2019<10.0.17763.5458
10.0.17763.5458
alpine/bind>=9.0.0<9.16.48-r0
9.16.48-r0
alpine/bind>=9.0.0<9.18.24-r0
9.18.24-r0
alpine/bind>=9.0.0<9.18.24-r0
9.18.24-r0
alpine/bind>=9.0.0<9.18.24-r0
9.18.24-r0
alpine/bind>=9.0.0<9.18.24-r0
9.18.24-r0
alpine/bind>=9.0.0<9.18.24-r0
9.18.24-r0
alpine/bind>=9.0.0<9.18.24-r0
9.18.24-r0
alpine/bind>=9.0.0<9.18.24-r0
9.18.24-r0
alpine/bind>=9.0.0<9.18.24-r0
9.18.24-r0
alpine/dnsmasq<2.90-r0
2.90-r0
alpine/dnsmasq<2.90-r0
2.90-r0
alpine/dnsmasq<2.90-r0
2.90-r0
alpine/dnsmasq<2.90-r0
2.90-r0
alpine/dnsmasq<2.90-r0
2.90-r0
alpine/dnsmasq<2.90-r0
2.90-r0
alpine/dnsmasq<2.90-r0
2.90-r0
alpine/dnsmasq<2.90-r0
2.90-r0
alpine/knot-resolver<5.7.1-r0
5.7.1-r0
alpine/knot-resolver<5.7.1-r0
5.7.1-r0
alpine/knot-resolver<5.7.1-r0
5.7.1-r0
alpine/knot-resolver<5.7.1-r0
5.7.1-r0
alpine/knot-resolver<5.7.1-r0
5.7.1-r0
alpine/knot-resolver<5.7.1-r0
5.7.1-r0
alpine/knot-resolver<5.7.1-r0
5.7.1-r0
alpine/pdns-recursor<4.9.3-r0
4.9.3-r0
alpine/pdns-recursor<4.9.3-r0
4.9.3-r0
alpine/pdns-recursor<5.0.2-r0
5.0.2-r0
alpine/pdns-recursor<5.0.2-r0
5.0.2-r0
alpine/pdns-recursor<5.0.2-r0
5.0.2-r0
alpine/pdns-recursor<5.0.2-r0
5.0.2-r0
alpine/pdns-recursor<5.0.2-r0
5.0.2-r0
alpine/unbound<1.19.1-r0
1.19.1-r0
alpine/unbound<1.19.1-r0
1.19.1-r0
alpine/unbound<1.19.1-r0
1.19.1-r0
alpine/unbound<1.19.1-r0
1.19.1-r0
alpine/unbound<1.19.1-r0
1.19.1-r0
alpine/unbound<1.19.1-r0
1.19.1-r0
alpine/unbound<1.19.1-r0
1.19.1-r0
alpine/unbound<1.19.1-r0
1.19.1-r0
debian/bind9
1:9.18.49-1~deb12u11:9.18.49-1~deb12u31:9.20.26-1~deb13u11:9.20.30-1~deb13u11:9.20.30-1
debian/dnsjava<=2.1.8-2
3.6.2-23.6.3-1
debian/dnsmasq
2.90-4~deb12u22.91-1+deb13u22.91-1+deb13u12.93-3
debian/knot-resolver
5.6.0-1+deb12u15.7.5-16.5.0-2
debian/pdns-recursor
4.8.8-1+deb12u15.2.13-0+deb13u15.4.9-1
debian/systemd
252.39-1~deb12u2252.38-1~deb12u1257.13-1~deb13u1262-1262.2-1
debian/unbound
1.17.1-2+deb12u41.17.1-2+deb12u31.22.0-2+deb13u31.26.2-0+deb13u11.26.2-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/bind to a version that resolves this vulnerability.

    Fixed in 9.16.48
  2. Upgrade

    Upgrade redhat/bind to a version that resolves this vulnerability.

    Fixed in 9.18.24
  3. Upgrade

    Upgrade redhat/bind to a version that resolves this vulnerability.

    Fixed in 9.19.21
  4. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 17.1.2
  5. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 16.1.6.1
  6. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 15.1.10.8
  7. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.3.9600.21813Patch KB5034819
  8. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.2.9200.24710Patch KB5034830
  9. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.1.7601.26961Patch KB5034809
  10. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.20348.2322Patch KB5034770
  11. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.14393.6709Patch KB5034767
  12. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.17763.5458Patch KB5034768
  13. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.25398.709Patch KB5034769
  14. Upgrade

    Upgrade alpine/bind to a version that resolves this vulnerability.

    Fixed in 9.16.48-r0
  15. Upgrade

    Upgrade alpine/bind to a version that resolves this vulnerability.

    Fixed in 9.18.24-r0
  16. Upgrade

    Upgrade alpine/dnsmasq to a version that resolves this vulnerability.

    Fixed in 2.90-r0
  17. Upgrade

    Upgrade alpine/knot-resolver to a version that resolves this vulnerability.

    Fixed in 5.7.1-r0
  18. Upgrade

    Upgrade alpine/pdns-recursor to a version that resolves this vulnerability.

    Fixed in 4.9.3-r0
  19. Upgrade

    Upgrade alpine/pdns-recursor to a version that resolves this vulnerability.

    Fixed in 5.0.2-r0
  20. Upgrade

    Upgrade alpine/unbound to a version that resolves this vulnerability.

    Fixed in 1.19.1-r0
  21. Upgrade

    Upgrade debian/bind9 to a version that resolves this vulnerability.

    Fixed in 1:9.18.49-1~deb12u1Fixed in 1:9.18.49-1~deb12u3Fixed in 1:9.20.26-1~deb13u1Fixed in 1:9.20.30-1~deb13u1Fixed in 1:9.20.30-1
  22. Upgrade

    Upgrade debian/dnsjava to a version that resolves this vulnerability.

    Fixed in 3.6.2-2Fixed in 3.6.3-1
  23. Upgrade

    Upgrade debian/dnsmasq to a version that resolves this vulnerability.

    Fixed in 2.90-4~deb12u2Fixed in 2.91-1+deb13u2Fixed in 2.91-1+deb13u1Fixed in 2.93-3
  24. Upgrade

    Upgrade debian/knot-resolver to a version that resolves this vulnerability.

    Fixed in 5.6.0-1+deb12u1Fixed in 5.7.5-1Fixed in 6.5.0-2
  25. Upgrade

    Upgrade debian/pdns-recursor to a version that resolves this vulnerability.

    Fixed in 4.8.8-1+deb12u1Fixed in 5.2.13-0+deb13u1Fixed in 5.4.9-1
  26. Upgrade

    Upgrade debian/systemd to a version that resolves this vulnerability.

    Fixed in 252.39-1~deb12u2Fixed in 252.38-1~deb12u1Fixed in 257.13-1~deb13u1Fixed in 262-1Fixed in 262.2-1
  27. Upgrade

    Upgrade debian/unbound to a version that resolves this vulnerability.

    Fixed in 1.17.1-2+deb12u4Fixed in 1.17.1-2+deb12u3Fixed in 1.22.0-2+deb13u3Fixed in 1.26.2-0+deb13u1Fixed in 1.26.2-1

Event History

Feb 13, 2024
CVE Published
via Ubuntu·12:00 AM
Data Sourced
via Ubuntu·12:00 AM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Microsoft·08:00 AM
DescriptionSeverityWeaknessAffected Software
News Published
via The Register·11:27 PM
Feb 14, 2024
CVE Published
via MITRE·12:00 AM
Data Sourced
via MITRE·12:00 AM
Description
Data Sourced
via NVD·04:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Data Sourced
via OSV·04:15 PM
DescriptionSeverityAffected Software
Feb 17, 2024
News Published
via BleepingComputer·04:08 PM
Feb 18, 2024
Exploit Published
via GitHub·09:50 PM
Mar 26, 2024
News Published
via The Register·08:24 AM
Mar 29, 2024
Advisory Published
via F5·04:55 PM
Data Sourced
via F5·04:55 PM
DescriptionSeverityWeaknessAffected Software
Feb 4, 2025
Data Sourced
via IBM·12:00 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

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.

2

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.

3

How do I fix CVE-2023-50387?

To fix CVE-2023-50387, apply the specific patches and updates provided by your software vendor.

4

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.

5

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.

Company

Resources

Contact

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