#VU22593 Input validation error in Knot Resolver - CVE-2019-10191

Vulnerability identifier: #VU22593

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2019-10191

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Knot Resolver
Server applications / Other server solutions

Vendor: Nic

Description

The vulnerability allows a remote attacker to hijack domain on the target system.

The vulnerability exists due to insufficient validation of user-supplied input in DNS resolver. A remote attacker can downgrade DNSSEC-secure domains to DNSSEC-insecure state, opening possibility of domain hijack using attacks against insecure DNS protocol.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Knot Resolver: 1.0 - 4.0.0

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External links
https://www.knot-resolver.cz/2019-07-10-knot-resolver-4.1.0.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.