Input validation error in unbound (Alpine package)

1) Input validation error

EUVDB-ID: #VU28161

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-2020-12662

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input when processing DNS responses. A remote attacker who controls a malicious DNS server can send a specially crafted response and perform a denial of service (DoS) attack against third-party DNS servers.

The attack is triggered by random subdomains in the NSDNAME in NS records.

Mitigation

Install update from vendor's website.

Vulnerable software versions

unbound (Alpine package): 1.4.13-r0 - 1.8.3-r3

CPE2.3

• cpe:2.3:a:alpine:unbound_alpine_package:1.4.13-r0:*:*:*:*:alpine_linux:*:2.3
• cpe:2.3:a:alpine:unbound_alpine_package:1.4.13-r3:*:*:*:*:alpine_linux:*:2.3
• cpe:2.3:a:alpine:unbound_alpine_package:1.4.13_p2-r0:*:*:*:*:alpine_linux:*:2.3

External links

https://git.alpinelinux.org/aports/commit/?id=3286876175392eea49a76b591165c2e940681c66
https://git.alpinelinux.org/aports/commit/?id=75675628d024650eb8edf60c6d81f67d3e563668
https://git.alpinelinux.org/aports/commit/?id=e09fa9fd69e509b0de3041baab65aac63b246b0d
https://git.alpinelinux.org/aports/commit/?id=2986d9e83b920ffacf364d4ee6c2a5644a330152

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.