Vulnerability identifier: #VU22894

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-6477

CWE-ID: CWE-399

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 incorrect implementation of TCP-pipelining feature in ISC BIND, aimed to limit the number of concurrent connections and protect the server from denial of service attacks. A remote attacker can initiate a TCP-pipelined connection with multiple queries that consume more resources than the server has been provisioned to handle and crash the server, when closing the connection.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.11.5-S6 - 9.15.5

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External links
http://kb.isc.org/docs/cve-2019-6477

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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.