Ubuntu update for bind9



Risk Medium
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2021-25220
CVE-2022-0396
CWE-ID CWE-350
CWE-399
Exploitation vector Network
Public exploit N/A
Vulnerable software
Subscribe 		Ubuntu
Operating systems & Components / Operating system

bind9 (Ubuntu package)
Operating systems & Components / Operating system package or component

Vendor Canonical Ltd.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Reliance on Reverse DNS Resolution for a Security-Critical Action

EUVDB-ID: #VU61422

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 - Reliance on Reverse DNS Resolution for a Security-Critical Action

Exploit availability: No

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

Update the affected package bind9 to the latest version.

Vulnerable software versions

Ubuntu: 18.04 - 21.10

bind9 (Ubuntu package): before 1:9.16.15-1ubuntu1.2

CPE2.3 External links

http://ubuntu.com/security/notices/USN-5332-1


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.

2) Resource management error

EUVDB-ID: #VU61423

Risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2022-0396

CWE-ID: CWE-399 - Resource Management Errors

Exploit availability: No

Description

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

The vulnerability exists due to improper management of internal resources within the application that allows TCP connection slots to be consumed for an indefinite time frame via a specifically crafted TCP stream sent from a client. A remote attacker can initiate a specially crafted TCP stream that can cause connections to BIND to remain in CLOSE_WAIT status for an indefinite period of time, even after the client has terminated the connection.

This issue can only be triggered on BIND servers which have keep-response-order enabled, which is not the default configuration. The keep-response-order option is an ACL block; any hosts which are specified within it will be able to trigger this issue on affected versions.

Mitigation

Update the affected package bind9 to the latest version.

Vulnerable software versions

Ubuntu: 18.04 - 21.10

bind9 (Ubuntu package): before 1:9.16.15-1ubuntu1.2

CPE2.3 External links

http://ubuntu.com/security/notices/USN-5332-1


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.



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