#VU45818 Reachable Assertion in ISC BIND - CVE-2020-8623

Vulnerability identifier: #VU45818

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-8623

CWE-ID: CWE-617

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ISC BIND
Server applications / DNS servers

Vendor: ISC

Description

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

The vulnerability exists due to a reachable assertion when processing DNS query for a zone signed with RSA. A remote attacker can send a specially crafted query and crash the DNS server.

Successful exploitation of the vulnerability requires that BIND is built with "--enable-native-pkcs11".

Mitigation
Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.10.0-P1 - 9.17.3

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External links
https://kb.isc.org/docs/cve-2020-8623

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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.