Domain Name System (DNS) Security Requirements Guide

The DNS Security Requirements Guide (SRG) is published as a tool to improve the security of Department of Defense (DoD) information systems. The requirements are derived from the NIST 800-53 and related documents. Comments or proposed revisions to this document should be sent via e-mail to the following address: [email protected]

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Version / Release: V2R4

Published: 2015-01-05

Updated At: 2018-09-23 02:26:11

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Drop CKL or SCAP (XCCDF) results here.

    Vuln Rule Version CCI Severity Title Description Status Finding Details Comments
    SV-69023r1_rule SRG-APP-000001-DNS-000115 CCI-000054 MEDIUM The DNS implementation must limit the number of concurrent sessions client connections to the number of allowed dynamic update clients. Limiting the number of concurrent sessions reduces the risk of Denial of Service (DoS) to the DNS implementation. Name servers do not have direct user connections but accept client connections for queries. Original restriction on client connections shou
    SV-69027r1_rule SRG-APP-000089-DNS-000004 CCI-000169 MEDIUM The DNS server implementation must be configured to provide audit record generation capability for DoD-defined auditable events within all DNS server components. Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident, or identify those responsible for one. The actual auditing is performed by the OS/NDM, but the configurati
    SV-69029r1_rule SRG-APP-000089-DNS-000005 CCI-000169 MEDIUM The DNS server implementation must be configured to provide audit record generation capability for DoD-defined auditable events within all DNS server components. Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident, or identify those responsible for one. The actual auditing is performed by the OS/NDM, but the configurati
    SV-69031r1_rule SRG-APP-000095-DNS-000006 CCI-000130 MEDIUM The DNS server implementation must produce audit records containing information to establish what type of events occurred. Auditing and logging are key components of any security architecture. It is essential for security personnel to know what is being performed on the system, where an event occurred, when an event occurred, and by whom the event was triggered, in order to c
    SV-69033r1_rule SRG-APP-000097-DNS-000008 CCI-000132 MEDIUM The DNS server implementation must produce audit records containing information to establish where the events occurred. Without establishing where events occurred, it is impossible to establish, correlate, and investigate the events relating to an incident. Associating information about where the event occurred within the application provides a means of investigating an at
    SV-69035r1_rule SRG-APP-000098-DNS-000009 CCI-000133 MEDIUM The DNS server implementation must produce audit records containing information to establish the source of the events. Without establishing the source of the event, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. Associating information about the source of the event within the application provides a means of investig
    SV-69037r1_rule SRG-APP-000099-DNS-000010 CCI-000134 MEDIUM The DNS server implementation must produce audit records that contain information to establish the outcome of the events. Without information about the outcome of events, security personnel cannot make an accurate assessment about whether an attack was successful or if changes were made to the security state of the system. Event outcomes can include indicators of event succ
    SV-69039r1_rule SRG-APP-000100-DNS-000011 CCI-001487 MEDIUM The DNS server implementation must generate audit records containing information that establishes the identity of any individual or process associated with the event. Without information that establishes the identity of the subjects (i.e., users or processes acting on behalf of users) associated with the events, security personnel cannot determine responsibility for the potentially harmful event. Event identifiers (if
    SV-69041r1_rule SRG-APP-000125-DNS-000012 CCI-001348 MEDIUM The DNS server implementations audit records must be backed up at least every seven days onto a different system or system component than the system or component being audited. Protection of log data includes assuring log data is not accidentally lost or deleted. Backing up audit records to a different system or onto separate media than the system being audited on a defined frequency helps to assure, in the event of a catastroph
    SV-69043r1_rule SRG-APP-000142-DNS-000014 CCI-000382 MEDIUM The DNS server implementation must be configured to prohibit or restrict unapproved ports and protocols. In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical po
    SV-69045r1_rule SRG-APP-000158-DNS-000015 CCI-000778 MEDIUM The DNS server implementation must uniquely identify the other DNS server before responding to a server-to-server transaction. Without identifying devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. This applies to server-to-server (zone transfer) transactions only and is provided by TSIG/SIG(0), which enforces mutual server authen
    SV-69047r1_rule SRG-APP-000176-DNS-000017 CCI-000186 MEDIUM The DNS server implementation, when using PKI-based authentication, must enforce authorized access to the corresponding private key. The cornerstone of the PKI is the private key used to encrypt or digitally sign information. If the private key is stolen, this will lead to the compromise of the authentication and non-repudiation gained through PKI because the attacker can use the priva
    SV-69049r1_rule SRG-APP-000176-DNS-000018 CCI-000186 MEDIUM The key file must be owned by the account under which the name server software is run. To enable zone transfer (requests and responses) through authenticated messages, it is necessary to generate a key for every pair of name servers. The key can also be used for securing other transactions, such as dynamic updates, DNS queries, and response
    SV-69051r1_rule SRG-APP-000176-DNS-000019 CCI-000186 MEDIUM Read/Write access to the key file must be restricted to the account that runs the name server software only. To enable zone transfer (requests and responses) through authenticated messages, it is necessary to generate a key for every pair of name servers. The key can also be used for securing other transactions, such as dynamic updates, DNS queries, and response
    SV-69053r1_rule SRG-APP-000176-DNS-000076 CCI-001339 MEDIUM A unique TSIG key must be generated for each pair of communicating hosts. To enable zone transfer (requests and responses) through authenticated messages, it is necessary to generate a key for every pair of name servers. The key also can be used for securing other transactions, such as dynamic updates, DNS queries, and response
    SV-69055r1_rule SRG-APP-000176-DNS-000094 CCI-000186 MEDIUM Only the private key corresponding to the ZSK alone must be kept on the name server that does support dynamic updates. The private keys in the KSK and ZSK key pairs must be protected from unauthorized access. If possible, the private keys should be stored off-line (with respect to the Internet-facing, DNSSEC-aware name server) in a physically secure, non-network-accessibl
    SV-69057r1_rule SRG-APP-000176-DNS-000096 CCI-000186 MEDIUM Signature generation using the KSK must be done off-line, using the KSK-private stored off-line. Security-relevant information is any information within information systems that can potentially impact the operation of security functions or the provision of security services in a manner that could result in failure to enforce system security policies
    SV-69059r1_rule SRG-APP-000185-DNS-000021 CCI-000877 MEDIUM The DNS server implementation must employ strong authenticators in the establishment of nonlocal maintenance and diagnostic sessions. If maintenance tools are used by unauthorized personnel, they may accidentally or intentionally damage or compromise the system. The act of managing systems and applications includes the ability to access sensitive application information, such as system
    SV-69061r1_rule SRG-APP-000213-DNS-000024 CCI-001178 MEDIUM A DNS server implementation must provide additional data origin artifacts along with the authoritative data the system returns in response to external name/address resolution queries. The underlying feature in the major threat associated with DNS query/response (i.e., forged response or response failure) is the integrity of DNS data returned in the response. The security objective is to verify the integrity of each response received. A
    SV-69063r1_rule SRG-APP-000214-DNS-000025 CCI-001179 MEDIUM A DNS server implementation must provide the means to indicate the security status of child zones. If name server replies are invalid or cannot be validated, many networking functions and communication would be adversely affected. With DNS, the presence of Delegation Signer (DS) records associated with child zones informs clients of the security status
    SV-69065r1_rule SRG-APP-000214-DNS-000079 CCI-001179 MEDIUM The validity period for the RRSIGs covering the DS RR for a zones delegated children must be no less than two days and no more than one week. The best way for a zone administrator to minimize the impact of a key compromise is by limiting the validity period of RRSIGs in the zone and in the parent zone. This strategy limits the time during which an attacker can take advantage of a compromised ke
    SV-69067r1_rule SRG-APP-000215-DNS-000003 CCI-001663 MEDIUM The DNS server implementation must enforce approved authorizations for controlling the flow of information between DNS servers and between DNS servers and DNS clients based on DNSSEC policies. A mechanism to detect and prevent unauthorized communication flow must be configured or provided as part of the system design. If information flow is not enforced based on approved authorizations, the system may become compromised. Information flow contro
    SV-69069r1_rule SRG-APP-000215-DNS-000026 CCI-001663 MEDIUM A DNS server implementation must provide the means to enable verification of a chain of trust among parent and child domains (if the child supports secure resolution services). If name server replies are invalid or cannot be validated, many networking functions and communication would be adversely affected. With DNS, the presence of Delegation Signer (DS) records associated with child zones informs clients of the security status
    SV-69071r1_rule SRG-APP-000219-DNS-000028 CCI-001184 MEDIUM The DNS implementation must protect the authenticity of communications sessions for zone transfers. DNS is a fundamental network service that is prone to various attacks, such as cache poisoning and man-in-the middle attacks. If communication sessions are not provided appropriate validity protections, such as the employment of DNSSEC, the authenticity
    SV-69073r1_rule SRG-APP-000219-DNS-000029 CCI-001184 MEDIUM The DNS implementation must protect the authenticity of communications sessions for dynamic updates. DNS is a fundamental network service that is prone to various attacks, such as cache poisoning and man-in-the middle attacks. If communication sessions are not provided appropriate validity protections, such as the employment of DNSSEC, the authenticity o
    SV-69075r1_rule SRG-APP-000219-DNS-000030 CCI-001184 MEDIUM The DNS implementation must protect the authenticity of communications sessions for queries. The underlying feature in the major threat associated with DNS query/response (i.e., forged response or response failure) is the integrity of DNS data returned in the response. An integral part of integrity verification is to ensure that valid data has or
    SV-69077r1_rule SRG-APP-000225-DNS-000031 CCI-001190 MEDIUM The DNS server implementation must fail to a secure state if system initialization fails, shutdown fails, or aborts fail. Failure to a known safe state helps prevent systems from failing to a state that may cause loss of data or unauthorized access to system resources. Applications or systems that fail suddenly and with no incorporated failure state planning may leave the ho
    SV-69079r1_rule SRG-APP-000226-DNS-000032 CCI-001665 MEDIUM In the event of a system failure, the DNS server implementation must preserve any information necessary to determine cause of failure and any information necessary to return to operations with least disruption to mission processes. Failure to a known state can address safety or security in accordance with the mission/business needs of the organization. Failure to a known secure state helps prevent a loss of confidentiality, integrity, or availability in the event of a failure of the
    SV-69081r1_rule SRG-APP-000231-DNS-000033 CCI-001199 MEDIUM The DNS server implementation must protect the confidentiality and integrity of secret/private cryptographic keys at rest and the integrity of DNS information at rest. Information at rest refers to the state of information when it is located on a secondary storage device within an organizational information system. Mobile devices, laptops, desktops, and storage devices can be either lost or stolen, and the contents of t
    SV-69083r1_rule SRG-APP-000243-DNS-000034 CCI-001090 MEDIUM The DNS server implementation must prevent unauthorized and unintended information transfer via shared system resources. Preventing unauthorized information transfers mitigates the risk of information, including encrypted representations of information, produced by the actions of prior users/roles (or the actions of processes acting on behalf of prior users/roles) from bein
    SV-69085r1_rule SRG-APP-000246-DNS-000035 CCI-001094 MEDIUM The DNS server implementation must restrict the ability of individuals to use the DNS server to launch Denial of Service (DoS) attacks against other information systems. A DoS is a condition where a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. Individuals of concern can include hostile insiders or external adv
    SV-69087r1_rule SRG-APP-000247-DNS-000036 CCI-001095 MEDIUM The DNS server implementation must manage excess capacity, bandwidth, or other redundancy to limit the effects of information flooding types of Denial of Service (DoS) attacks. A DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. In the case of application DoS attacks, care must be taken when des
    SV-69089r1_rule SRG-APP-000251-DNS-000037 CCI-001310 MEDIUM The DNS server implementation must check the validity of all data inputs except those specifically identified by the organization. Invalid user input occurs when a user inserts data or characters into an application's data entry fields and the application is unprepared to process that data. This results in unanticipated application behavior, potentially leading to an application or i
    SV-69091r1_rule SRG-APP-000275-DNS-000040 CCI-001294 MEDIUM The DNS server implementation must be configured to generate audit records for failed security verification tests so that the ISSO and ISSM can be notified of the failures. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality i
    SV-69093r1_rule SRG-APP-000333-DNS-000104 CCI-002201 MEDIUM The DNS Name Server software must be configured to refuse queries for its version information. Each newer version of the name server software, especially the BIND software, generally is devoid of vulnerabilities found in earlier versions because it has design changes incorporated to take care of those vulnerabilities. Of course, these vulnerabiliti
    SV-69095r1_rule SRG-APP-000333-DNS-000107 CCI-002201 MEDIUM The HINFO, RP, TXT and LOC RR types must not be used in the zone SOA. There are several types of RRs in the DNS that are meant to convey information to humans and applications about the network, hosts, or services. These RRs include the Responsible Person (RP) record, the Host Information (HINFO) record, the Location (LOC)
    SV-69097r1_rule SRG-APP-000353-DNS-000045 CCI-001914 MEDIUM The DNS server implementation must be configured to allow DNS administrators to change the auditing to be performed on all DNS server components, based on all selectable event criteria. If authorized individuals do not have the ability to modify auditing parameters in response to a changing threat environment, the organization may not be able to effectively respond, and important forensic information may be lost. This requirement enable
    SV-69099r1_rule SRG-APP-000001-DNS-000001 CCI-000054 MEDIUM The DNS implementation must limit the number of concurrent sessions for zone transfers to the number of secondary name servers. Limiting the number of concurrent sessions reduces the risk of Denial of Service (DoS) to the DNS implementation. Name servers do not have direct user connections but accept client connections for queries. Original restriction on client connections shou
    SV-69101r2_rule SRG-APP-000383-DNS-000047 CCI-000366 MEDIUM The DNS implementation must prohibit recursion on authoritative name servers. A potential vulnerability of DNS is that an attacker can poison a name server's cache by sending queries that will cause the server to obtain host-to-IP address mappings from bogus name servers that respond with incorrect information. Once a name server h
    SV-69103r1_rule SRG-APP-000390-DNS-000048 CCI-002039 MEDIUM The DNS server implementation must require devices to re-authenticate for each zone transfer and dynamic update request connection attempt. Without re-authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. In addition to the re-authentication requirements associated with session locks, organizations may require re-authentication of
    SV-69107r1_rule SRG-APP-000394-DNS-000049 CCI-001958 MEDIUM The DNS server implementation must authenticate the other DNS server before responding to a server-to-server transaction. Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. Device authentication is a solution enabling an organization to manage devices. It is an additional layer of authentication ensurin
    SV-69109r1_rule SRG-APP-000395-DNS-000050 CCI-001967 MEDIUM The DNS server implementation must authenticate another DNS server before establishing a remote and/or network connection using bidirectional authentication that is cryptographically based. Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. Bidirectional authentication provides stronger safeguards to validate the identity of other devices for connections that are of gre
    SV-69111r1_rule SRG-APP-000401-DNS-000051 CCI-001991 MEDIUM The DNS server implementation, for PKI-based authentication, must implement a local cache of revocation data to support path discovery and validation in case of the inability to access revocation information via the network. Without configuring a local cache of revocation data, there is the potential to allow access to users who are no longer authorized (users with revoked certificates). SIG(0) is used for server-to-server authentication for DNS transactions, and it uses PK
    SV-69113r1_rule SRG-APP-000420-DNS-000053 CCI-000366 MEDIUM A DNS server implementation must provide data origin artifacts for internal name/address resolution queries. The major threat associated with DNS forged responses or failures is the integrity of the DNS data returned in the response. The principle of DNSSEC is to mitigate this threat by providing data origin authentication, establishing trust in the source. This
    SV-69115r1_rule SRG-APP-000421-DNS-000054 CCI-000366 MEDIUM A DNS server implementation must provide data integrity protection artifacts for internal name/address resolution queries. The major threat associated with DNS forged responses or failures is the integrity of the DNS data returned in the response. The principle of DNSSEC is to mitigate this threat by providing data origin authentication, establishing trust in the source. This
    SV-69117r1_rule SRG-APP-000422-DNS-000055 CCI-002462 MEDIUM A DNS server implementation must provide additional integrity artifacts along with the authoritative name resolution data the system returns in response to external name/address resolution queries. The major threat associated with DNS forged responses or failures is the integrity of the DNS data returned in the response. The principle of DNSSEC is to mitigate this threat by providing data origin authentication, establishing trust in the source. This
    SV-69119r1_rule SRG-APP-000423-DNS-000056 CCI-002465 MEDIUM A DNS server implementation must request data origin authentication verification on the name/address resolution responses the system receives from authoritative sources. If data origin authentication and data integrity verification are not performed, the resultant response could be forged, it may have come from a poisoned cache, the packets could have been intercepted without the resolver's knowledge, or resource records
    SV-69121r1_rule SRG-APP-000424-DNS-000057 CCI-002466 MEDIUM A DNS server implementation must request data integrity verification on the name/address resolution responses the system receives from authoritative sources. If data origin authentication and data integrity verification are not performed, the resultant response could be forged, it may have come from a poisoned cache, the packets could have been intercepted without the resolver's knowledge, or resource records
    SV-69123r1_rule SRG-APP-000425-DNS-000058 CCI-002467 MEDIUM A DNS server implementation must perform data integrity verification on the name/address resolution responses the system receives from authoritative sources. If data origin authentication and data integrity verification are not performed, the resultant response could be forged, it may have come from a poisoned cache, the packets could have been intercepted without the resolver's knowledge, or resource records
    SV-69131r1_rule SRG-APP-000426-DNS-000059 CCI-002468 MEDIUM A DNS server implementation must perform data origin verification authentication on the name/address resolution responses the system receives from authoritative sources. If data origin authentication and data integrity verification are not performed, the resultant response could be forged, it may have come from a poisoned cache, the packets could have been intercepted without the resolver's knowledge, or resource records
    SV-69133r1_rule SRG-APP-000427-DNS-000060 CCI-002470 MEDIUM If the DNS server is using SIG(0), the DNS server implementation must only allow the use of DoD PKI-established certificate authorities for verification of the establishment of protected transactions. Untrusted Certificate Authorities (CA) can issue certificates, but they may be issued by organizations or individuals that seek to compromise DoD systems or by organizations with insufficient security controls. If the CA used for verifying the certificate
    SV-69135r1_rule SRG-APP-000429-DNS-000062 CCI-002476 MEDIUM The DNS server implementation must utilize cryptographic mechanisms to prevent unauthorized disclosure of non-DNS data stored on the DNS server. Applications handling data requiring "data-at-rest" protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest. Selection of a cryptographic mechanism is based on the need to protect th
    SV-69137r1_rule SRG-APP-000439-DNS-000063 CCI-002418 MEDIUM The DNS server implementation must protect the integrity of transmitted information. Without protection of the transmitted information, confidentiality and integrity may be compromised since unprotected communications can be intercepted and either read or altered. Communication paths outside the physical protection of a controlled bound
    SV-69141r1_rule SRG-APP-000440-DNS-000065 CCI-002421 MEDIUM The DNS server implementation must implement cryptographic mechanisms to detect changes to information during transmission unless otherwise protected by alternative physical safeguards, such as, at a minimum, a Protected Distribution System (PDS). Encrypting information for transmission protects information from unauthorized disclosure and modification. Cryptographic mechanisms implemented to protect information integrity include, for example, cryptographic hash functions which have common applicat
    SV-69143r1_rule SRG-APP-000441-DNS-000066 CCI-002420 MEDIUM The DNS server implementation must maintain the integrity of information during preparation for transmission. Information can be either unintentionally or maliciously disclosed or modified during preparation for transmission, including, for example, during aggregation, at protocol transformation points, and during packing/unpacking. These unauthorized disclosures
    SV-69145r1_rule SRG-APP-000442-DNS-000067 CCI-002422 MEDIUM The DNS server implementation must maintain the integrity of information during reception. Information can be either unintentionally or maliciously disclosed or modified during reception, including, for example, during aggregation, at protocol transformation points, and during packing/unpacking. These unauthorized disclosures or modifications c
    SV-69147r1_rule SRG-APP-000447-DNS-000068 CCI-002754 MEDIUM The DNS server implementation must behave in a predictable and documented manner that reflects organizational and system objectives when invalid inputs are received. A common vulnerability of applications is unpredictable behavior when invalid inputs are received. This requirement guards against adverse or unintended system behavior caused by invalid inputs, where information system responses to the invalid input may
    SV-69149r1_rule SRG-APP-000451-DNS-000069 CCI-000366 MEDIUM The DNS server implementation must follow procedures to re-role a secondary name server as the master name server should the master name server permanently lose functionality. Failing to an unsecure condition negatively impacts application security and can lead to system compromise. Failure conditions include, for example, loss of communications among critical system components or between system components and operational facil
    SV-69151r1_rule SRG-APP-000473-DNS-000072 CCI-002699 MEDIUM The DNS server implementation must perform verification of the correct operation of security functions: upon system start-up and/or restart; upon command by a user with privileged access; and/or every 30 days. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality i
    SV-69153r1_rule SRG-APP-000474-DNS-000073 CCI-002702 MEDIUM The DNS server implementation must log the event and notify the system administrator when anomalies in the operation of the signed zone transfers are discovered. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality i
    SV-69155r1_rule SRG-APP-000504-DNS-000074 CCI-000172 MEDIUM The DNS implementation must generate audit records for the success and failure of start and stop of the name server service or daemon. Auditing and logging are key components of any security architecture. It is essential for security personnel to know what is being performed on the system, where an event occurred, when an event occurred, and by whom the event was triggered, in order to c
    SV-69157r1_rule SRG-APP-000504-DNS-000082 CCI-000172 MEDIUM The DNS implementation must generate audit records for the success and failure of all name server events. Auditing and logging are key components of any security architecture. It is essential for security personnel to know what is being performed on the system, where an event occurred, when an event occurred, and by whom the event was triggered, in order to c
    SV-69161r1_rule SRG-APP-000514-DNS-000075 CCI-002450 MEDIUM The DNS server must implement NIST FIPS-validated cryptography for provisioning digital signatures, generating cryptographic hashes, and protecting unclassified information requiring confidentiality. Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The application must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides ass
    SV-69163r1_rule SRG-APP-000516-DNS-000077 CCI-000366 MEDIUM The salt value for zones signed using NSEC3 RRs must be changed every time the zone is completely re-signed. NSEC3 RRs contain other options than just the (hashed) next name and RRType bitmap. There are also 2 values associated with the NSEC3 RR: the iterations (number of times each name is hashed) and the salt (string appended to each name before hashing). Thes
    SV-69165r1_rule SRG-APP-000516-DNS-000078 CCI-000366 MEDIUM The validity period for the RRSIGs covering a zones DNSKEY RRSet must be no less than two days and no more than one week. The best way for a zone administrator to minimize the impact of a key compromise is by limiting the validity period of RRSIGs in the zone and in the parent zone. This strategy limits the time during which an attacker can take advantage of a compromised ke
    SV-69167r1_rule SRG-APP-000516-DNS-000084 CCI-000366 MEDIUM NSEC3 must be used for all internal DNS zones. To ensure that RRs associated with a query are really missing in a zone file and have not been removed in transit, the DNSSEC mechanism provides a means for authenticating the nonexistence of an RR. It generates a special RR called an NSEC (or NSEC3) RR t
    SV-69169r1_rule SRG-APP-000516-DNS-000085 CCI-000366 MEDIUM The DNS implementation must ensure each NS record in a zone file points to an active name server authoritative for the domain specified in that record. Poorly constructed NS records pose a security risk because they create conditions under which an adversary might be able to provide the missing authoritative name services that are improperly specified in the zone file. The adversary could issue bogus res
    SV-69171r1_rule SRG-APP-000516-DNS-000086 CCI-000366 MEDIUM The two files generated by the dnssec-keygen program must be made accessible only to the server administrator account, or deleted, after they have been copied to the key file in the name server. To enable zone transfer (requests and responses) through authenticated messages, it is necessary to generate a key for every pair of name servers. The key also can be used for securing other transactions, such as dynamic updates, DNS queries, and response
    SV-69173r1_rule SRG-APP-000516-DNS-000087 CCI-000366 MEDIUM All authoritative name servers for a zone must be located on different network segments. Most enterprises have an authoritative primary server and a host of authoritative secondary name servers. It is essential that these authoritative name servers for an enterprise be located on different network segments. This dispersion ensures the availab
    SV-69175r1_rule SRG-APP-000516-DNS-000088 CCI-000366 MEDIUM All authoritative name servers for a zone must have the same version of zone information. The only protection approach for content control of DNS zone file is the use of a zone file integrity checker. The effectiveness of integrity checking using a zone file integrity checker depends upon the database of constraints built into the checker. The
    SV-69177r1_rule SRG-APP-000516-DNS-000089 CCI-000366 MEDIUM An authoritative name server must be configured to enable DNSSEC Resource Records. The specification for a digital signature mechanism in the context of the DNS infrastructure is in IETF's DNSSEC standard. In DNSSEC, trust in the public key (for signature verification) of the source is established not by going to a third party or a cha
    SV-69179r1_rule SRG-APP-000516-DNS-000091 CCI-000366 MEDIUM For zones split between the external and internal sides of a network, the RRs for the external hosts must be separate from the RRs for the internal hosts. Authoritative name servers for an enterprise may be configured to receive requests from both external and internal clients. External clients need to receive RRs that pertain only to public services (public Web server, mail server, etc.) Internal clien
    SV-69181r1_rule SRG-APP-000516-DNS-000092 CCI-000366 MEDIUM In a split DNS configuration, where separate name servers are used between the external and internal networks, the external name server must be configured to not be reachable from inside resolvers. Instead of having the same set of authoritative name servers serve different types of clients, an enterprise could have two different sets of authoritative name servers. One set, called external name servers, can be located within a DMZ; these would be
    SV-69183r1_rule SRG-APP-000516-DNS-000093 CCI-000366 MEDIUM In a split DNS configuration, where separate name servers are used between the external and internal networks, the internal name server must be configured to not be reachable from outside resolvers. Instead of having the same set of authoritative name servers serve different types of clients, an enterprise could have two different sets of authoritative name servers. One set, called external name servers, can be located within a DMZ; these would be
    SV-69185r1_rule SRG-APP-000516-DNS-000095 CCI-000366 MEDIUM Primary authoritative name servers must be configured to only receive zone transfer requests from specified secondary name servers. Authoritative name servers (especially primary name servers) should be configured with an allow-transfer access control substatement designating the list of hosts from which zone transfer requests can be accepted. These restrictions address the denial-of-
    SV-69187r1_rule SRG-APP-000516-DNS-000097 CCI-000366 MEDIUM The DNS implementation must be conformant to the IETF DNS specification. Any DNS implementation must be designed to be able to conform to the Internet Engineering Task Force (IETF) specification. DoD utilizes many different DNS servers, and it is essential that core capabilities of all are compatible. DNS servers that do not p
    SV-69189r1_rule SRG-APP-000516-DNS-000099 CCI-000366 MEDIUM The DNS implementation must enforce a Discretionary Access Control (DAC) policy that limits propagation of access rights. Discretionary Access Control (DAC) is based on the premise that individual users are "owners" of objects and therefore have discretion over who should be authorized to access the object and in which mode (e.g., read or write). Ownership is usually acquire
    SV-69191r1_rule SRG-APP-000516-DNS-000101 CCI-000366 MEDIUM The DNS implementation must implement internal/external role separation. DNS servers with an internal role only process name/address resolution requests from within the organization (i.e., internal clients). DNS servers with an external role only process name/address resolution information requests from clients external to the
    SV-69193r1_rule SRG-APP-000516-DNS-000102 CCI-000366 MEDIUM The DNS must utilize valid root name servers in the local root zone file. All caching name servers must be authoritative for the root zone because, without this starting point, they would have no knowledge of the DNS infrastructure and thus would be unable to respond to any queries. The security risk is that an adversary could
    SV-69195r1_rule SRG-APP-000516-DNS-000103 CCI-000366 MEDIUM The DNS name server software must be at the latest version. Each newer version of the name server software, especially the BIND software, generally is devoid of vulnerabilities found in earlier versions because it has design changes incorporated to take care of those vulnerabilities. These vulnerabilities have bee
    SV-69197r1_rule SRG-APP-000516-DNS-000105 CCI-000366 MEDIUM The DNS Name Server software must run with restricted privileges. Failure to provide logical access restrictions associated with changes to application configuration may have significant effects on the overall security of the system. When dealing with access restrictions pertaining to change control, it should be noted
    SV-69199r1_rule SRG-APP-000516-DNS-000108 CCI-000366 MEDIUM The IP address for hidden master authoritative name servers must not appear in the name servers set in the zone database. A hidden master authoritative server is an authoritative DNS server whose IP address does not appear in the name server set for a zone. All of the name servers that do appear in the zone database as designated name servers get their zone data from the hi
    SV-69201r1_rule SRG-APP-000516-DNS-000109 CCI-000366 MEDIUM The platform on which the name server software is hosted must be configured to respond to DNS traffic only. OS configuration practices as issued by the US Computer Emergency Response Team (US CERT) and the National Institute of Standards and Technology's (NIST's) National Vulnerability Database (NVD), based on identified vulnerabilities that pertain to the appl
    SV-69203r1_rule SRG-APP-000516-DNS-000110 CCI-000366 MEDIUM The platform on which the name server software is hosted must be configured to send outgoing DNS messages from a random port. OS configuration practices as issued by the US Computer Emergency Response Team (US CERT) and the National Institute of Standards and Technology's (NIST's) National Vulnerability Database (NVD), based on identified vulnerabilities that pertain to the appl
    SV-69205r1_rule SRG-APP-000516-DNS-000111 CCI-000366 MEDIUM The private key corresponding to the ZSK, stored on name servers accepting dynamic updates, must have appropriate directory/file-level access control list-based or cryptography-based protections. The private keys in the KSK and ZSK key pairs must be protected from unauthorized access. If possible, the private keys should be stored off-line (with respect to the Internet-facing, DNSSEC-aware name server) in a physically secure, non-network-accessibl
    SV-69207r1_rule SRG-APP-000516-DNS-000112 CCI-000366 MEDIUM The private keys corresponding to both the ZSK and the KSK must not be kept on the DNSSEC-aware primary authoritative name server when the name server does not support dynamic updates. The private keys in the KSK and ZSK key pairs must be protected from unauthorized access. If possible, the private keys should be stored off-line (with respect to the Internet-facing, DNSSEC-aware name server) in a physically secure, non-network-accessibl
    SV-69209r1_rule SRG-APP-000516-DNS-000113 CCI-000366 MEDIUM A zone file must not include resource records that resolve to a fully qualified domain name residing in another zone. If a name server were able to claim authority for a resource record in a domain for which it was not authoritative, this would pose a security risk. In this environment, an adversary could use illicit control of a name server to impact IP address resoluti
    SV-69211r1_rule SRG-APP-000516-DNS-000114 CCI-000366 MEDIUM CNAME records must not point to a zone with lesser security for more than six months. The use of CNAME records for exercises, tests, or zone-spanning aliases should be temporary (e.g., to facilitate a migration). When a host name is an alias for a record in another zone, an adversary has two points of attack: the zone in which the alias is
    SV-69213r1_rule SRG-APP-000218-DNS-000027 CCI-000366 MEDIUM All authoritative name servers for a zone must be geographically disbursed. In addition to network-based dispersion, authoritative name servers should be dispersed geographically as well. In other words, in addition to being located on different network segments, the authoritative name servers should not all be located within the
    SV-69215r1_rule SRG-APP-000268-DNS-000039 CCI-000366 MEDIUM The DNS server implementation must, when a component failure is detected, activate a notification to the system administrator. Predictable failure prevention requires organizational planning to address system failure issues. If components key to maintaining systems security fail to function, the system could continue operating in an insecure state. The organization must be prepar
    SV-69217r1_rule SRG-APP-000347-DNS-000041 CCI-000366 MEDIUM The DNS server implementation must strongly bind the identity of the DNS server with the DNS information. Weakly bound credentials can be modified without invalidating the credential; therefore, non-repudiation can be violated. This requirement supports audit requirements that provide organizational personnel with the means to identify who produced specific
    SV-69219r1_rule SRG-APP-000348-DNS-000042 CCI-000366 MEDIUM The DNS server implementation must provide the means for authorized individuals to determine the identity of the source of the DNS server-provided information. Without a means for identifying the individual that produced the information, the information cannot be relied upon. Identifying the validity of information may be delayed or deterred. This requirement provides organizational personnel with the means to
    SV-69221r1_rule SRG-APP-000349-DNS-000043 CCI-000366 MEDIUM The DNS server implementation must validate the binding of the other DNS servers identity to the DNS information for a server-to-server transaction (e.g., zone transfer). Validation of the binding of the information prevents the modification of information between production and review. The validation of bindings can be achieved, for example, by the use of cryptographic checksums. Validations must be performed automaticall
    SV-69223r1_rule SRG-APP-000350-DNS-000044 CCI-000366 MEDIUM In the event of an error when validating the binding of another DNS servers identity to the DNS information, the DNS server implementation must log the event and send notification to the DNS administrator. Failing to act on the validation errors may result in the use of invalid, corrupted, or compromised information. The validation of bindings can be achieved, for example, by the use of cryptographic checksums. Validations must be performed automatically.
    SV-69225r1_rule SRG-APP-000516-DNS-000090 CCI-000366 MEDIUM Digital signature algorithm used for DNSSEC-enabled zones must be FIPS-compatible. The choice of digital signature algorithm will be based on recommended algorithms in well-known standards. NIST's Digital Signature Standard (DSS) [FIPS186] provides three algorithm choices: * Digital Signature Algorithm (DSA) * RSA * Elliptic Curve DSA (
    SV-69471r1_rule SRG-APP-000096-DNS-000007 CCI-000131 MEDIUM The DNS server implementation must produce audit records containing information to establish when (date and time) the events occurred. Without establishing when events occurred, it is impossible to establish, correlate, and investigate the events relating to an incident. Associating event types with detected events in the application and audit logs provides a means of investigating an
    SV-69473r1_rule SRG-APP-000428-DNS-000061 CCI-002475 MEDIUM The DNS server implementation must utilize cryptographic mechanisms to prevent unauthorized modification of DNS zone data. Applications handling data requiring "data at rest" protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest. Selection of a cryptographic mechanism is based on the need to protect th
    SV-69475r1_rule SRG-APP-000516-DNS-000500 CCI-000366 MEDIUM The DNS server implementation must be configured in accordance with the security configuration settings based on DoD security configuration or implementation guidance, including STIGs, NSA configuration guides, CTOs, and DTMs. Configuration settings are the set of parameters that can be changed that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the application, including the param