#VU47532 Input validation error in PowerDNS Recursor - CVE-2020-25829

Vulnerability identifier: #VU47532

Vulnerability risk: Medium

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

CVE-ID: CVE-2020-25829

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PowerDNS Recursor
Server applications / DNS servers

Vendor: PowerDNS.COM B.V.

Description

The vulnerability allows a remote attacker to perform cache poisoning attack.

The vulnerability exists due to insufficient validation of user-supplied input. A remote attacker can cause the cached records for a given name to be updated to the ‘Bogus’ DNSSEC validation state, instead of their actual DNSSEC ‘Secure’ state, via a DNS ANY query. This results in a denial of service for installations that always validate (dnssec=validate) and for clients requesting validation when on-demand validation is enabled (dnssec=process).

Mitigation
Install updates from vendor's website.

Vulnerable software versions

PowerDNS Recursor: 4.0.0 rc1 - 4.0.9, 4.1.0 rc1 - 4.1.17, 4.2.0 alpha1 - 4.2.4, 4.3.0 rc1 - 4.3.4, 4.4.0 alpha1

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External links
https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2020-07.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.