Denial of service in Unbound

1) Resource exhaustion

EUVDB-ID: #VU69407

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-2022-3204

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: No

Description

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

The vulnerability exists due to application does not properly control consumption of internal resources when processing a malicious delegation with a considerable number of non responsive nameservers. A remote attacker can trigger CPU high usage and perform a denial of service (DoS) attack.

The attack is known as "Non-Responsive Delegation Attack" (NRDelegation Attack).

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Unbound: 1.0.0 - 1.16.2

CPE2.3

• cpe:2.3:a:unbound_net:unbound:1.0.0:*:*:*:*:*:*:*
• cpe:2.3:a:unbound_net:unbound:1.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:unbound_net:unbound:1.0.2:*:*:*:*:*:*:*

External links

https://www.nlnetlabs.nl/downloads/unbound/CVE-2022-3204.txt

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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