http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8616 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8616 ISC BIND is vulnerable to a denial of service, caused by the failure to limit the number of fetches performed when processing referrals. By using specially crafted referrals, a remote attacker could exploit this vulnerability to cause the recursing server to issue a very large number of fetches in an attempt to process the referral. ISC BIND is vulnerable to a denial of service, caused by a logic error in code which checks TSIG validity. A remote attacker could exploit this vulnerability to trigger an assertion failure in tsig.c.

According to the versions of the bind packages installed, the EulerOS Virtualization installation on the remote host is affected by the following vulnerabilities :

  - Bind-utils contains a collection of utilities for     querying DNS (Domain Name System) name servers to find     out information about Internet hosts. These tools will     provide you with the IP addresses for given host names,     as well as other information about registered domains     andnetwork addresses.You should install bind-utils if     you need to get information from DNS name     servers.Security Fix(es):In BIND 9.10.0 -> 9.11.21,     9.12.0 -> 9.16.5, 9.17.0 -> 9.17.3, also affects     9.10.5-S1 -> 9.11.21-S1 of the BIND 9 Supported Preview     Edition, An attacker that can reach a vulnerable system     with a specially crafted query packet can trigger a     crash. To be vulnerable, the system must: * be running     BIND that was built with '--enable-native-pkcs11' * be     signing one or more zones with an RSA key * be able to     receive queries from a possible     attacker(CVE-2020-8623)A malicious actor who     intentionally exploits this lack of effective     limitation on the number of fetches performed when     processing referrals can, through the use of specially     crafted referrals, cause a recursing server to issue a     very large number of fetches in an attempt to process     the referral. This has at least two potential effects:
    The performance of the recursing server can potentially     be degraded by the additional work required to perform     these fetches, and The attacker can exploit this     behavior to use the recursing server as a reflector in     a reflection attack with a high amplification     factor.(CVE-2020-8616)Using a specially-crafted     message, an attacker may potentially cause a BIND     server to reach an inconsistent state if the attacker     knows (or successfully guesses) the name of a TSIG key     used by the server. Since BIND, by default, configures     a local session key even on servers whose configuration     does not otherwise make use of it, almost all current     BIND servers are vulnerable. In releases of BIND dating     from March 2018 and after, an assertion check in tsig.c     detects this inconsistent state and deliberately exits.
    Prior to the introduction of the check the server would     continue operating in an inconsistent state, with     potentially harmful results.(CVE-2020-8617)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for bind fixes the following issues :

BIND was upgraded to version 9.16.6 :

Note :

bind is now more strict in regards to DNSSEC. If queries are not working, check for DNSSEC issues. For instance, if bind is used in a namserver forwarder chain, the forwarding DNS servers must support DNSSEC.

Fixing security issues :

CVE-2020-8616: Further limit the number of queries that can be triggered from a request. Root and TLD servers are no longer exempt from max-recursion-queries. Fetches for missing name server.
(bsc#1171740) Address records are limited to 4 for any domain.

CVE-2020-8617: Replaying a TSIG BADTIME response as a request could trigger an assertion failure. (bsc#1171740)

CVE-2019-6477: Fixed an issue where TCP-pipelined queries could bypass the tcp-clients limit (bsc#1157051).

CVE-2018-5741: Fixed the documentation (bsc#1109160).

CVE-2020-8618: It was possible to trigger an INSIST when determining whether a record would fit into a TCP message buffer (bsc#1172958).

CVE-2020-8619: It was possible to trigger an INSIST in lib/dns/rbtdb.c:new_reference() with a particular zone content and query patterns (bsc#1172958).

CVE-2020-8624: 'update-policy' rules of type 'subdomain' were incorrectly treated as 'zonesub' rules, which allowed keys used in 'subdomain' rules to update names outside of the specified subdomains.
The problem was fixed by making sure 'subdomain' rules are again processed as described in the ARM (bsc#1175443).

CVE-2020-8623: When BIND 9 was compiled with native PKCS#11 support, it was possible to trigger an assertion failure in code determining the number of bits in the PKCS#11 RSA public key with a specially crafted packet (bsc#1175443).

CVE-2020-8621: named could crash in certain query resolution scenarios where QNAME minimization and forwarding were both enabled (bsc#1175443).

CVE-2020-8620: It was possible to trigger an assertion failure by sending a specially crafted large TCP DNS message (bsc#1175443).

CVE-2020-8622: It was possible to trigger an assertion failure when verifying the response to a TSIG-signed request (bsc#1175443).

Other issues fixed :

Add engine support to OpenSSL EdDSA implementation.

Add engine support to OpenSSL ECDSA implementation.

Update PKCS#11 EdDSA implementation to PKCS#11 v3.0.

Warn about AXFR streams with inconsistent message IDs.

Make ISC rwlock implementation the default again.

Fixed issues when using cookie-secrets for AES and SHA2 (bsc#1161168)

Installed the default files in /var/lib/named and created chroot environment on systems using transactional-updates (bsc#1100369, fate#325524)

Fixed an issue where bind was not working in FIPS mode (bsc#906079).

Fixed dependency issues (bsc#1118367 and bsc#1118368).

GeoIP support is now discontinued, now GeoIP2 is used(bsc#1156205).

Fixed an issue with FIPS (bsc#1128220).

The liblwres library is discontinued upstream and is no longer included.

Added service dependency on NTP to make sure the clock is accurate when bind is starts (bsc#1170667, bsc#1170713).

Reject DS records at the zone apex when loading master files. Log but otherwise ignore attempts to add DS records at the zone apex via UPDATE.

The default value of 'max-stale-ttl' has been changed from 1 week to 12 hours.

Zone timers are now exported via statistics channel.

The 'primary' and 'secondary' keywords, when used as parameters for 'check-names', were not processed correctly and were being ignored.

'rndc dnstap -roll <value>' did not limit the number of saved files to <value>.

Add 'rndc dnssec -status' command.

Addressed a couple of situations where named could crash.

Changed /var/lib/named to owner root:named and perms rwxrwxr-t so that named, being a/the only member of the 'named' group has full r/w access yet cannot change directories owned by root in the case of a compromized named. [bsc#1173307, bind-chrootenv.conf]

Added '/etc/bind.keys' to NAMED_CONF_INCLUDE_FILES in /etc/sysconfig/named to suppress warning message re missing file (bsc#1173983).

Removed '-r /dev/urandom' from all invocations of rndc-confgen (init/named system/lwresd.init system/named.init in vendor-files) as this option is deprecated and causes rndc-confgen to fail.
(bsc#1173311, bsc#1176674, bsc#1170713)

/usr/bin/genDDNSkey: Removing the use of the -r option in the call of /usr/sbin/dnssec-keygen as BIND now uses the random number functions provided by the crypto library (i.e., OpenSSL or a PKCS#11 provider) as a source of randomness rather than /dev/random. Therefore the -r command line option no longer has any effect on dnssec-keygen. Leaving the option in genDDNSkey as to not break compatibility. Patch provided by Stefan Eisenwiener. [bsc#1171313]

Put libns into a separate subpackage to avoid file conflicts in the libisc subpackage due to different sonums (bsc#1176092).

Require /sbin/start_daemon: both init scripts, the one used in systemd context as well as legacy sysv, make use of start_daemon.

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Redhat Enterprise Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2020:2383 advisory.

    The Berkeley Internet Name Domain (BIND) is an implementation of the Domain Name System (DNS) protocols.
    BIND includes a DNS server (named); a resolver library (routines for applications to use when interfacing     with DNS); and tools for verifying that the DNS server is operating correctly.

    Security Fix(es):

    * bind: BIND does not sufficiently limit the number of fetches performed when processing referrals     (CVE-2020-8616)

    * bind: A logic error in code which checks TSIG validity can be used to trigger an assertion failure in     tsig.c (CVE-2020-8617)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2020:3378 advisory.

    The Berkeley Internet Name Domain (BIND) is an implementation of the Domain Name System (DNS) protocols.
    BIND includes a DNS server (named); a resolver library (routines for applications to use when interfacing     with DNS); and tools for verifying that the DNS server is operating correctly.

    Security Fix(es):

    * bind: BIND does not sufficiently limit the number of fetches performed when processing referrals     (CVE-2020-8616)

    * bind: A logic error in code which checks TSIG validity can be used to trigger an assertion failure in     tsig.c (CVE-2020-8617)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Several vulnerabilities were discovered in BIND, a DNS server implementation.

  - CVE-2019-6477     It was discovered that TCP-pipelined queries can bypass     tcp-client limits resulting in denial of service.

  - CVE-2020-8616     It was discovered that BIND does not sufficiently limit     the number of fetches performed when processing     referrals. An attacker can take advantage of this flaw     to cause a denial of service (performance degradation)     or use the recursing server in a reflection attack with     a high amplification factor.

  - CVE-2020-8617     It was discovered that a logic error in the code which     checks TSIG validity can be used to trigger an assertion     failure, resulting in denial of service.

The remote CentOS Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2020:2344 advisory.

  - A malicious actor who intentionally exploits this lack of effective limitation on the number of fetches     performed when processing referrals can, through the use of specially crafted referrals, cause a recursing     server to issue a very large number of fetches in an attempt to process the referral. This has at least     two potential effects: The performance of the recursing server can potentially be degraded by the     additional work required to perform these fetches, and The attacker can exploit this behavior to use the     recursing server as a reflector in a reflection attack with a high amplification factor. (CVE-2020-8616)

  - Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an     inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the     server. Since BIND, by default, configures a local session key even on servers whose configuration does     not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating     from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately     exits. Prior to the introduction of the check the server would continue operating in an inconsistent     state, with potentially harmful results. (CVE-2020-8617)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Latest minor release with security updates.

  - [Upstream release     notes](https://downloads.isc.org/isc/bind9/9.11.19/RELEA     SE-NOTES-bind-9.11.19.html)

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2020:2345 advisory.

    The Berkeley Internet Name Domain (BIND) is an implementation of the Domain Name System (DNS) protocols.
    BIND includes a DNS server (named); a resolver library (routines for applications to use when interfacing     with DNS); and tools for verifying that the DNS server is operating correctly.

    Security Fix(es):

    * bind: BIND does not sufficiently limit the number of fetches performed when processing referrals     (CVE-2020-8616)

    * bind: A logic error in code which checks TSIG validity can be used to trigger an assertion failure in     tsig.c (CVE-2020-8617)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Published	Updated	Severity
139754	AIX 7.2 TL 3 : bind (IJ25926)	Nessus	AIX Local Security Checks	8/24/2020	4/21/2023	high
139755	AIX 7.2 TL 4 : bind (IJ25927)	Nessus	AIX Local Security Checks	8/24/2020	4/21/2023	high
151902	EulerOS Virtualization 3.0.2.2 : bind (EulerOS-SA-2021-2127)	Nessus	Huawei Local Security Checks	7/21/2021	12/7/2023	high
143842	SUSE SLED15 / SLES15 Security Update : bind (SUSE-SU-2020:2914-1)	Nessus	SuSE Local Security Checks	12/9/2020	5/11/2022	medium
137070	RHEL 6 : bind (RHSA-2020:2383)	Nessus	Red Hat Local Security Checks	6/3/2020	11/7/2024	high
139462	RHEL 6 : bind (RHSA-2020:3378)	Nessus	Red Hat Local Security Checks	8/10/2020	11/8/2024	high
136721	Debian DSA-4689-1 : bind9 - security update	Nessus	Debian Local Security Checks	5/20/2020	3/12/2024	high
137007	CentOS 7 : bind (RHSA-2020:2344)	Nessus	CentOS Local Security Checks	6/2/2020	10/9/2024	high
137124	Fedora 31 : 32:bind / bind-dyndb-ldap / dnsperf (2020-f9dcd4e9d5)	Nessus	Fedora Local Security Checks	6/4/2020	3/7/2024	high
137063	RHEL 8 : bind (RHSA-2020:2345)	Nessus	Red Hat Local Security Checks	6/3/2020	11/7/2024	high

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