SB2020110929 - Red Hat Enterprise Linux 8 update for bind
Published: November 9, 2020
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 secuirty vulnerabilities.
1) Reachable Assertion (CVE-ID: CVE-2020-8619)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a reachable assertion when processing entries with an asterisk ("*") character in rbtdb.c. Unless a nameserver is providing authoritative service for one or more zones and at least one zone contains an empty non-terminal entry containing an asterisk ("*") character, an attacker with ability to change zone content can trigger assertion failure and perform a denial of service (DoS) attack.
Note, this vulnerability may affect hosting provider that allow users access to domain management functionality.
2) Reachable Assertion (CVE-ID: CVE-2020-8622)
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.
3) Reachable Assertion (CVE-ID: CVE-2020-8623)
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".
4) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-8624)
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.
Remediation
Install update from vendor's website.