Input validation error in pdns-recursor (Alpine package)

1) Input validation error

EUVDB-ID: #VU47532

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 - Improper input validation

Exploit availability: No

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 update from vendor's website.

Vulnerable software versions

pdns-recursor (Alpine package): 4.0.4-r0 - 4.3.5-r0

CPE2.3

• cpe:2.3:o:alpine:pdns-recursor_alpine_package:4.0.4-r0:*:*:*:*:alpine_linux:*:3.4
• cpe:2.3:o:alpine:pdns-recursor_alpine_package:4.0.4-r2:*:*:*:*:alpine_linux:*:3.5
• cpe:2.3:o:alpine:pdns-recursor_alpine_package:4.0.7-r0:*:*:*:*:alpine_linux:*:3.6

External links

https://git.alpinelinux.org/aports/commit/?id=0a3b521c9ae76af008676cd4ae4a8c0fc30e927a

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.