CVE-2020-8616

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.

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.

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.

Updated bind packages fix security vulnerabilities:

It was discovered that Bind incorrectly handled certain TCP-pipelined queries. A remote attacker could possibly use this issue to cause Bind to consume resources, resulting in a denial of service (CVE-2019-6477).

Lior Shafir, Yehuda Afek, and Anat Bremler-Barr discovered that Bind incorrectly limited certain fetches. A remote attacker could possibly use this issue to cause Bind to consume resources, leading to a denial of service, or possibly use Bind to perform a reflection attack (CVE-2020-8616).

Tobias Klein discovered that Bind incorrectly handled checking TSIG validity. A remote attacker could use this issue to cause Bind to crash, resulting in a denial of service, or possibly perform other attacks (CVE-2020-8617).

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…

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…

These are all security issues fixed in the bind-9.16.20-1.4 package on the GA media of openSUSE Tumbleweed.

This update for bind fixes the following issues:

Security issues fixed:

• CVE-2020-8616: Fixed the insufficient limit on the number of fetches performed when processing referrals (bsc#1171740).
• CVE-2020-8617: Fixed a logic error in code which checks TSIG validity (bsc#1171740).

Non-security issue fixed:

• Fixed an invalid string comparison in the handling of cookie-secrets (bsc#1161168).

This update for bind fixes the following issues:

• CVE-2020-8616: Fixed the insufficient limit on the number of fetches performed when processing referrals (bsc#1171740).
• CVE-2020-8617: Fixed a logic error in code which checks TSIG validity (bsc#1171740).
• CVE-2018-5741: Fixed the documentation (bsc#1109160).
• Removed rndc.key generation from bind.spec file (bsc#1092283, bsc#1033843) bind should create the key on first boot or if it went missing.

This update for bind fixes the following issues:

• Amended documentation referring to rule types 'krb5-subdomain' and 'ms-subdomain'. This incorrect documentation could mislead operators into believing that policies they had configured were more restrictive than they actually were. [CVE-2018-5741]

• 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 address records are limited to 4 for any domain. [CVE-2020-8616]

• Replaying a TSIG BADTIME response as a request could trigger an assertion failure. [CVE-2020-8617] [bsc#1109160, bsc#1171740, CVE-2018-5741, bind-CVE-2018-5741.patch, CVE-2020-8616, bind-CVE-2020-8616.patch, CVE-2020-8617, bind-CVE-2020-8617.patch]

• Don't rely on /etc/insserv.conf anymore for proper dependencies against nss-lookup.target in named.service and lwresd.service (bsc#1118367 bsc#1118368)

• Using a drop-in file

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…

Lior Shafir, Yehuda Afek, and Anat Bremler-Barr discovered that Bind incorrectly limited certain fetches. A remote attacker could possibly use this issue to cause Bind to consume resources, leading to a denial of service, or possibly use Bind to perform a reflection attack. (CVE-2020-8616)

Tobias Klein discovered that Bind incorrectly handled checking TSIG validity. A remote attacker could use this issue to cause Bind to crash, resulting in a denial of service, or possibly perform other attacks. (CVE-2020-8617)

USN-4365-1 fixed several vulnerabilities in Bind. This update provides the corresponding update for Ubuntu 12.04 ESM and 14.04 ESM.

Original advisory details:

Lior Shafir, Yehuda Afek, and Anat Bremler-Barr discovered that Bind incorrectly limited certain fetches. A remote attacker could possibly use this issue to cause Bind to consume resources, leading to a denial of service, or possibly use Bind to perform a reflection attack. (CVE-2020-8616)

Tobias Klein discovered that Bind incorrectly handled checking TSIG validity. A remote attacker could use this issue to cause Bind to crash, resulting in a denial of service, or possibly perform other attacks. (CVE-2020-8617)