CVE-2019-6477

With pipelining enabled each incoming query on a TCP connection requires a similar resource allocation to a query received via UDP or via TCP without pipelining enabled. A client using a TCP-pipelined connection to a server could consume more resources than the server has been provisioned to handle. When a TCP connection with a large number of pipelined queries is closed, the load on the server releasing these multiple resources can cause it to become unresponsive, even for queries that can be answered authoritatively or from cache. (This is most likely to be perceived as an intermittent server problem).

With pipelining enabled each incoming query on a TCP connection requires a similar resource allocation to a query received via UDP or via TCP without pipelining enabled. A client using a TCP-pipelined connection to a server could consume more resources than the server has been provisioned to handle. When a TCP connection with a large number of pipelined queries is closed, the load on the server releasing these multiple resources can cause it to become unresponsive, even for queries that can be answered authoritatively or from cache. (This is most likely to be perceived as an intermittent server problem).

With pipelining enabled each incoming query on a TCP connection requires a similar resource allocation to a query received via UDP or via TCP without pipelining enabled. A client using a TCP-pipelined connection to a server could consume more resources than the server has been provisioned to handle. When a TCP connection with a large number of pipelined queries is closed, the load on the server releasing these multiple resources can cause it to become unresponsive, even for queries that can be answered authoritatively or from cache. (This is most likely to be perceived as an intermittent server problem).

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:

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…

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.