Ubuntu update for Unbound

Published: 2020-05-28

Risk	Medium
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2020-12662 CVE-2020-12663
CWE-ID	CWE-20 CWE-835
Exploitation vector	Network
Public exploit	N/A
Vulnerable software	unbound (Ubuntu package) Operating systems & Components / Operating system package or component
Vendor	Canonical Ltd.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

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

Update the affected packages.

Ubuntu 20.04 LTS: libunbound8 - 1.9.4-2ubuntu1.1; unbound - 1.9.4-2ubuntu1.1
Ubuntu 19.10: libunbound8 - 1.9.0-2ubuntu1.1; unbound - 1.9.0-2ubuntu1.1
Ubuntu 18.04 LTS: libunbound2 - 1.6.7-1ubuntu2.3; unbound - 1.6.7-1ubuntu2.3

Vulnerable software versions

unbound (Ubuntu package): 1.6.0-1 - 1.9.4-2

CPE2.3

External links

https://usn.ubuntu.com/4374-1/

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.

2) Infinite loop

EUVDB-ID: #VU28163