In BIND 9.0.0 -> 9.11.21, 9.12.0 -> 9.16.5, 9.17.0 -> 9.17.3, also affects 9.9.3-S1 -> 9.11.21-S1 of the BIND 9 Supported Preview Edition, 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. Alternately, an off-path attacker would have to correctly guess when a TSIG-signed request was sent, along with other characteristics of the packet and message, and spoof a truncated response to trigger an assertion failure, causing the server to exit.

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.

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.

To provide fine-grained controls over the ability to use Dynamic DNS (DDNS) to update records in a zone, BIND 9 provides a feature called update-policy. Various rules can be configured to limit the types of updates that can be performed by a client, depending on the key used when sending the update request. Unfortunately, some rule types were not initially documented, and when documentation for them was added to the Administrator Reference Manual (ARM) in change #3112, the language that was added to the ARM at that time incorrectly described the behavior of two 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. This affects BIND versions prior to BIND 9.11.5 and BIND 9.12.3.

named in ISC BIND 9.x before 9.9.9-P5, 9.10.x before 9.10.4-P5, and 9.11.x before 9.11.0-P2 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a crafted DS resource record in an answer.

named in ISC BIND 9.x before 9.9.9-P5, 9.10.x before 9.10.4-P5, and 9.11.x before 9.11.0-P2 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a malformed response to an RTYPE ANY query.

named in ISC BIND 9.x before 9.9.9-P4, 9.10.x before 9.10.4-P4, and 9.11.x before 9.11.0-P1 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a DNAME record in the answer section of a response to a recursive query, related to db.c and resolver.c.

ISC BIND 9.1.0 through 9.8.4-P2 and 9.9.0 through 9.9.2-P2 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via malformed options data in an OPT resource record.

ISC BIND 9.x before 9.9.9-P2, 9.10.x before 9.10.4-P2, and 9.11.x before 9.11.0b2, when lwresd or the named lwres option is enabled, allows remote attackers to cause a denial of service (daemon crash) via a long request that uses the lightweight resolver protocol.

ISC BIND through 9.9.9-P1, 9.10.x through 9.10.4-P1, and 9.11.x through 9.11.0b1 allows primary DNS servers to cause a denial of service (secondary DNS server crash) via a large AXFR response, and possibly allows IXFR servers to cause a denial of service (IXFR client crash) via a large IXFR response and allows remote authenticated users to cause a denial of service (primary DNS server crash) via a large UPDATE message.

named in ISC BIND 9.x before 9.9.8-P4 and 9.10.x before 9.10.3-P4 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a crafted signature record for a DNAME record, related to db.c and resolver.c.

named in ISC BIND 9.x before 9.9.8-P4 and 9.10.x before 9.10.3-P4 does not properly handle DNAME records when parsing fetch reply messages, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a malformed packet to the rndc (aka control channel) interface, related to alist.c and sexpr.c.

buffer.c in named in ISC BIND 9.10.x before 9.10.3-P3, when debug logging is enabled, allows remote attackers to cause a denial of service (REQUIRE assertion failure and daemon exit, or daemon crash) or possibly have unspecified other impact via (1) OPT data or (2) an ECS option.

apl_42.c in ISC BIND 9.x before 9.9.8-P3, 9.9.x, and 9.10.x before 9.10.3-P3 allows remote authenticated users to cause a denial of service (INSIST assertion failure and daemon exit) via a malformed Address Prefix List (APL) record.

Race condition in resolver.c in named in ISC BIND 9.9.8 before 9.9.8-P2 and 9.10.3 before 9.10.3-P2 allows remote attackers to cause a denial of service (INSIST assertion failure and daemon exit) via unspecified vectors.

db.c in named in ISC BIND 9.x before 9.9.8-P2 and 9.10.x before 9.10.3-P2 allows remote attackers to cause a denial of service (REQUIRE assertion failure and daemon exit) via a malformed class attribute.

ISC BIND 9.0.x through 9.8.x, 9.9.0 through 9.9.6, and 9.10.0 through 9.10.1 does not limit delegation chaining, which allows remote attackers to cause a denial of service (memory consumption and named crash) via a large or infinite number of referrals.

ISC BIND 9.x before 9.7.6-P4, 9.8.x before 9.8.3-P4, 9.9.x before 9.9.1-P4, and 9.4-ESV and 9.6-ESV before 9.6-ESV-R7-P4 allows remote attackers to cause a denial of service (named daemon hang) via unspecified combinations of resource records.

ISC BIND 9.x before 9.7.6-P3, 9.8.x before 9.8.3-P3, 9.9.x before 9.9.1-P3, and 9.4-ESV and 9.6-ESV before 9.6-ESV-R7-P3 allows remote attackers to cause a denial of service (assertion failure and named daemon exit) via a query for a long resource record.

ISC BIND 9.x before 9.7.6-P1, 9.8.x before 9.8.3-P1, 9.9.x before 9.9.1-P1, and 9.4-ESV and 9.6-ESV before 9.6-ESV-R7-P1 does not properly handle resource records with a zero-length RDATA section, which allows remote DNS servers to cause a denial of service (daemon crash or data corruption) or obtain sensitive information from process memory via a crafted record.