Denial of service in Unbound

1) Buffer overflow

EUVDB-ID: #VU29237

Risk: Medium

CVSSv3.1: 6.4 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-16866

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

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

The vulnerability exists due to a boundary error when processing NOTIFY queries in Unbound. A remote attacker can send a specially crafted NOTIFY query, trigger uninitialized memory access and crash the service.

Successful exploitation of this vulnerability requires that the source IP address of the query matches an access-control rule.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Unbound: 1.9.0 - 1.9.3 rc2

External links

http://github.com/NLnetLabs/unbound/blob/release-1.9.4/doc/Changelog
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/E65NCWZZB2D75ZIYWPXKMVGSGNYW4JMC/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MLRHE7TQFAOV4MB2ELTOGESZYUL65NUJ/
http://nlnetlabs.nl/downloads/unbound/CVE-2019-16866.txt
http://seclists.org/bugtraq/2019/Oct/23
http://usn.ubuntu.com/4149-1/
http://www.debian.org/security/2019/dsa-4544

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.