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Merge branch 'pspacek/doc-and-build-tweaks' into 'main'
Describe BIND threat model See merge request isc-projects/bind9!8364
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Security Configurations
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Security Configurations
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=======================
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=======================
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Security Assumptions
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--------------------
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BIND 9's design assumes that access to the objects listed below is limited only to
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trusted parties. An incorrect deployment, which does not follow rules set by this
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section, cannot be the basis for CVE assignment or special security-sensitive
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handling of issues.
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Unauthorized access can potentially disclose sensitive data, slow down server
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operation, etc. Unauthorized, unexpected, or incorrect writes to listed objects
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can potentically cause crashes, incorrect data handling, or corruption.
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- All files stored on disk - including zone files, configuration files, key
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files, temporary files, etc.
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- Clients communicating via :any:`controls` socket using configured keys
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- Access to :any:`statistics-channels` from untrusted clients
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- Sockets used for :any:`update-policy` type `external`
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Certain aspects of the DNS protocol are left unspecified, such as the handling of
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responses from DNS servers which do not fully conform to the DNS protocol. For
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such a situation, BIND implements its own safety checks and limits which are
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subject to change as the protocol and deployment evolve.
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Authoritative Servers
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~~~~~~~~~~~~~~~~~~~~~
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By default, zones use intentionally lenient limits (unlimited size, long
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transfer timeouts, etc.). These defaults can be misused by the source of data
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(zone transfers or UPDATEs) to exhaust resources on the receiving side.
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The impact of malicious zone changes can be limited, to an extent, using
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configuration options listed in sections :ref:`server_resource_limits` and
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:ref:`zone_transfers`. Limits should also be applied to zones where malicious clients may potentially be authorized to use :ref:`dynamic_update`.
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DNS Resolvers
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~~~~~~~~~~~~~
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By definition, DNS resolvers act as traffic amplifiers;
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during normal operation, a DNS resolver can legitimately generate more outgoing
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traffic (counted in packets or bytes) than the incoming client traffic that
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triggered it. The DNS protocol specification does not currently specify limits
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for this amplification, but BIND implements its own limits to balance
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interoperability and safety. As a general rule, if a traffic amplification factor
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for any given scenario is lower than 100 packets, ISC does not handle the given
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scenario as a security issue. These limits are subject to change as DNS
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deployment evolves.
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All DNS answers received by the DNS resolver are treated as untrusted input and are
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subject to safety and correctness checks. However, protocol non-conformity
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might cause unexpected behavior. If such unexpected behavior is limited to DNS
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domains hosted on non-conformant servers, it is not deemed a security issue *in
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BIND*.
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.. _file_permissions:
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.. _file_permissions:
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.. _access_Control_Lists:
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.. _access_Control_Lists:
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1
tests/bench/.gitignore
vendored
1
tests/bench/.gitignore
vendored
@@ -4,5 +4,6 @@
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/dns_name_fromwire
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/dns_name_fromwire
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/load-names
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/load-names
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/qp-dump
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/qp-dump
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/qplookups
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/qpmulti
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/qpmulti
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/siphash
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/siphash
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