Vulnerability identifier: #VU61422

Vulnerability risk: Medium

CVSSv3.1: 5.9 [CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-25220

CWE-ID: CWE-350

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ISC BIND
Server applications / DNS servers

Vendor: ISC

Description

The vulnerability allows a remote attacker to poison DNS cache.

The vulnerability exists due to an error in DNS forwarder implementation. When using forwarders, bogus NS records supplied by, or via, those forwarders may be cached and used by named if it needs to recurse for any reason, causing it to obtain and pass on potentially incorrect answers. The cache could become poisoned with incorrect records leading to queries being made to the wrong servers, which might also result in false information being returned to clients.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.11.0 - 9.18.0

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External links
http://kb.isc.org/docs/cve-2021-25220

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated privileged user via the Internet.

Is there known malware, which exploits this vulnerability?

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