Multiple vulnerabilities in ISC BIND



Published: 2020-08-20
Risk Medium
Patch available YES
Number of vulnerabilities 5
CVE-ID CVE-2020-8620
CVE-2020-8621
CVE-2020-8622
CVE-2020-8623
CVE-2020-8624
CWE-ID CWE-617
CWE-264
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
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ISC BIND
Server applications / DNS servers

Vendor ISC

Security Bulletin

This security bulletin contains information about 5 vulnerabilities.

1) Reachable Assertion

EUVDB-ID: #VU45821

Risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-8620

CWE-ID: CWE-617 - Reachable Assertion

Exploit availability: Yes

Description

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

The vulnerability exists due to a reachable assertion in tcpdns.c when processing large TCP payloads. An attacker who can establish a TCP connection with the server and send data on that connection can exploit this to trigger the assertion failure, causing the server to exit.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.15.0 - 9.17.3


CPE2.3 External links

http://kb.isc.org/docs/cve-2020-8620

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. However, proof of concept for this vulnerability is available.

2) Reachable Assertion

EUVDB-ID: #VU45820

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-2020-8621

CWE-ID: CWE-617 - Reachable Assertion

Exploit availability: No

Description

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

The vulnerability exists due to a reachable assertion in resolver.c while attempting QNAME minimization after forwarding. If a server is configured with both QNAME minimization and 'forward first' then an attacker who can send queries to it may be able to trigger the condition that will cause the server to crash.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.14.0 - 9.17.3


CPE2.3 External links

http://kb.isc.org/docs/cve-2020-8621

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.

3) Reachable Assertion

EUVDB-ID: #VU45819

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-8622

CWE-ID: CWE-617 - Reachable Assertion

Exploit availability: No

Description

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

The vulnerability exists due to a reachable assertion when handling TSIG-signed request. An attacker on the network path for a TSIG-signed request, or operating the server receiving the TSIG-signed request, could send a truncated response to that request, triggering an assertion failure, causing the server to exit.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.0 - 9.17.3


CPE2.3 External links

http://kb.isc.org/docs/cve-2020-8622

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user 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.

4) Reachable Assertion

EUVDB-ID: #VU45818

Risk: Medium

CVSSv3.1: 5.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-8623

CWE-ID: CWE-617 - Reachable Assertion

Exploit availability: No

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 - 9.17.3


CPE2.3 External links

http://kb.isc.org/docs/cve-2020-8623

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.

5) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU45817

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-8624

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a remote user to perform unauthorized actions.

The vulnerability exists due to change 4885 in BIND inadvertently caused "update-policy" rules of type "subdomain" to be treated as if they were of type "zonesub", allowing updates to all parts of the zone along with the intended subdomain. A remote user with privileges to change a specific subset of the zone's content could abuse these unintended additional privileges to update other contents of the zone.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

ISC BIND: 9.9.12 - 9.17.3


CPE2.3 External links

http://kb.isc.org/docs/cve-2020-8624

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user 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.



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