4771(F): Kerberos pre-hallmark failed.

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Event 4771 illustration

Subcategory:  Audit Kerberos Authentication Service

Result Clarification:

This effect generates every fourth dimension the Central Distribution Heart fails to issue a Kerberos Ticket Granting Ticket (TGT). This trouble can occur when a domain controller doesn't have a certificate installed for smart bill of fare authentication (for example, with a "Domain Controller" or "Domain Controller Authentication" template), the user'south countersign has expired, or the wrong password was provided.

This upshot generates only on domain controllers.

This event is not generated if "Do not crave Kerberos preauthentication" option is set for the account.

Note  For recommendations, see Security Monitoring Recommendations for this event.

Event XML: 

              - <Issue xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> - <Organisation>  <Provider Name="Microsoft-Windows-Security-Auditing" Guid="{54849625-5478-4994-A5BA-3E3B0328C30D}" />   <EventID>4771</EventID>   <Version>0</Version>   <Level>0</Level>   <Task>14339</Job>   <Opcode>0</Opcode>   <Keywords>0x8010000000000000</Keywords>   <TimeCreated SystemTime="2015-08-07T18:x:21.495462300Z" />   <EventRecordID>166708</EventRecordID>   <Correlation />   <Execution ProcessID="520" ThreadID="1084" />   <Channel>Security</Channel>   <Calculator>DC01.contoso.local</Computer>   <Security />   </System> - <EventData>  <Data Name="TargetUserName">dadmin</Information>   <Data Name="TargetSid">S-i-v-21-3457937927-2839227994-823803824-1104</Data>   <Data Proper noun="ServiceName">krbtgt/CONTOSO.LOCAL</Data>   <Data Name="TicketOptions">0x40810010</Information>   <Data Name="Condition">0x10</Data>   <Data Name="PreAuthType">xv</Data>   <Data Name="IpAddress">::ffff:10.0.0.12</Data>   <Data Proper name="IpPort">49254</Data>   <Data Name="CertIssuerName" />   <Data Name="CertSerialNumber" />   <Data Proper name="CertThumbprint" />   </EventData>  </Event>

Required Server Roles: Active Directory domain controller.

Minimum Os Version: Windows Server 2008.

Event Versions: 0.

Field Descriptions:

Account Data:

  • Security ID [Type = SID]: SID of account object for which (TGT) ticket was requested. Result Viewer automatically tries to resolve SIDs and show the business relationship name. If the SID cannot be resolved, you will see the source data in the upshot.

    For example: CONTOSO\dadmin or CONTOSO\WIN81$.

Note  A security identifier (SID) is a unique value of variable length used to place a trustee (security principal). Each business relationship has a unique SID that is issued by an authority, such as an Agile Directory domain controller, and stored in a security database. Each time a user logs on, the system retrieves the SID for that user from the database and places information technology in the access token for that user. The system uses the SID in the access token to identify the user in all subsequent interactions with Windows security. When a SID has been used as the unique identifier for a user or group, it cannot e'er be used again to place another user or group. For more data about SIDs, see Security identifiers.

  • Business relationship Name: [Blazon = UnicodeString]: the proper noun of account, for which (TGT) ticket was requested. Reckoner business relationship name ends with $ character.

    • User business relationship example: dadmin

    • Figurer business relationship case: WIN81$

Service Information:

  • Service Name [Type = UnicodeString]: the proper noun of the service in the Kerberos Realm to which TGT asking was sent. Typically has ane of the following formats:

    • krbtgt/DOMAIN_NETBIOS_NAME. Example: krbtgt/CONTOSO

    • krbtgt/DOMAIN_FULL_NAME. Case: krbtgt/CONTOSO.LOCAL

Network Information:

  • Customer Address [Blazon = UnicodeString]: IP accost of the computer from which the TGT request was received. Here are some examples of formats:

    • IPv6 or IPv4 address.

    • ::ffff:IPv4_address.

    • ::1 - localhost.

  • Client Port [Type = UnicodeString]: source port number of client network connectedness (TGT asking connectedness).

    • 0 for local (localhost) requests.

Additional Information:

  • Ticket Options: [Type = HexInt32]: this set of different Ticket Flags is in hexadecimal format.

    Case:

    • Ticket Options: 0x40810010

    • Binary view: 01000000100000010000000000010000

    • Using MSB 0-bit numbering, we have chip 1, 8, 15 and 27 set = Forwardable, Renewable, Canonicalize, Renewable-ok.

Note  In the table beneath "MSB 0" bit numbering is used, because RFC documents use this style. In "MSB 0" style bit numbering begins from left.
MSB illustration

The virtually common values:

  • 0x40810010 - Forwardable, Renewable, Canonicalize, Renewable-ok

  • 0x40810000 - Forwardable, Renewable, Canonicalize

  • 0x60810010 - Forwardable, Forwarded, Renewable, Canonicalize, Renewable-ok

Bit Flag Name Description
0 Reserved -
1 Forwardable (TGT only). Tells the ticket-granting service that it tin can issue a new TGT—based on the presented TGT—with a dissimilar network address based on the presented TGT.
2 Forwarded Indicates either that a TGT has been forwarded or that a ticket was issued from a forwarded TGT.
three Proxiable (TGT simply). Tells the ticket-granting service that information technology can event tickets with a network address that differs from the one in the TGT.
four Proxy Indicates that the network address in the ticket is different from the one in the TGT used to obtain the ticket.
5 Let-postdate Postdated tickets SHOULD NOT exist supported in KILE (Microsoft Kerberos Protocol Extension).
6 Postdated Postdated tickets SHOULD NOT be supported in KILE (Microsoft Kerberos Protocol Extension).
7 Invalid This flag indicates that a ticket is invalid, and information technology must exist validated by the KDC earlier use. Awarding servers must reject tickets that have this flag fix.
viii Renewable Used in combination with the End Time and Renew Till fields to crusade tickets with long life spans to be renewed at the KDC periodically.
nine Initial Indicates that a ticket was issued using the authentication service (As) exchange and non issued based on a TGT.
10 Pre-authent Indicates that the client was authenticated by the KDC before a ticket was issued. This flag commonly indicates the presence of an authenticator in the ticket. It can also flag the presence of credentials taken from a smart card logon.
11 Opt-hardware-auth This flag was originally intended to indicate that hardware-supported authentication was used during pre-hallmark. This flag is no longer recommended in the Kerberos V5 protocol. KDCs MUST Not issue a ticket with this flag set. KDCs SHOULD Not preserve this flag if information technology is gear up by another KDC.
12 Transited-policy-checked KILE MUST NOT bank check for transited domains on servers or a KDC. Application servers MUST ignore the TRANSITED-POLICY-CHECKED flag.
thirteen Ok-as-delegate The KDC MUST fix the OK-AS-Delegate flag if the service business relationship is trusted for delegation.
14 Request-anonymous KILE does not apply this flag.
15 Name-canonicalize To request referrals, the Kerberos client MUST explicitly request the "canonicalize" KDC pick for the Every bit-REQ or TGS-REQ.
16-25 Unused -
26 Disable-transited-check By default the KDC will check the transited field of a TGT against the policy of the local realm before it will issue derivative tickets based on the TGT. If this flag is set in the request, checking of the transited field is disabled. Tickets issued without the performance of this check will be noted by the reset (0) value of the TRANSITED-POLICY-CHECKED flag, indicating to the application server that the transited field must exist checked locally. KDCs are encouraged but not required to honour
the DISABLE-TRANSITED-CHECK option.
Should not be in use, because Transited-policy-checked flag is not supported by KILE.
27 Renewable-ok The RENEWABLE-OK choice indicates that a renewable ticket will be acceptable if a ticket with the requested life cannot otherwise be provided, in which example a renewable ticket may be issued with a renew-till equal to the requested end fourth dimension. The value of the renew-till field may still be limited past local limits, or limits selected past the individual principal or server.
28 Enc-tkt-in-skey No data.
29 Unused -
30 Renew The RENEW option indicates that the present request is for a renewal. The ticket provided is encrypted in the hugger-mugger key for the server on which it is valid. This option will only be honored if the ticket to be renewed has its RENEWABLE flag set and if the time in its renew-till field has not passed. The ticket to be renewed is passed in the padata field as part of the authentication header.
31 Validate This choice is used only by the ticket-granting service. The VALIDATE choice indicates that the asking is to validate a postdated ticket. Should non be in employ, because postdated tickets are not supported by KILE.

Table 6. Kerberos ticket flags.

  • Failure Code [Type = HexInt32]: hexadecimal failure code of failed TGT issue functioning. The table below contains the list of the error codes for this event as defined in RFC 4120:
Code Code Name Clarification Possible causes
0x0 KDC_ERR_NONE No error
0x1 KDC_ERR_NAME_EXP Client's entry in database has expired
0x2 KDC_ERR_SERVICE_EXP Server's entry in database has expired
0x3 KDC_ERR_BAD_PVNO Requested protocol version number not supported
0x4 KDC_ERR_C_OLD_MAST_KVNO Client's cardinal encrypted in old master key
0x5 KDC_ERR_S_OLD_MAST_KVNO Server's primal encrypted in old primary primal
0x6 KDC_ERR_C_PRINCIPAL_UNKNOWN Client not plant in Kerberos database
0x7 KDC_ERR_S_PRINCIPAL_UNKNOWN Server not found in Kerberos database
0x8 KDC_ERR_PRINCIPAL_NOT_UNIQUE Multiple principal entries in database
0x9 KDC_ERR_NULL_KEY The customer or server has a null key
0xa KDC_ERR_CANNOT_POSTDATE Ticket non eligible for postdating
0xb KDC_ERR_NEVER_VALID Requested starttime is after than end time
0xc KDC_ERR_POLICY KDC policy rejects request
0xd KDC_ERR_BADOPTION KDC cannot accommodate requested option
0xe KDC_ERR_ETYPE_NOSUPP KDC has no back up for encryption blazon
0xf KDC_ERR_SUMTYPE_NOSUPP KDC has no support for checksum blazon
0x10 KDC_ERR_PADATA_TYPE_NOSUPP KDC has no support for PADATA type (pre-hallmark data) Smart card logon is being attempted and the proper certificate cannot be located. This problem can happen because the wrong certification authority (CA) is being queried or the proper CA cannot be contacted in order to become Domain Controller or Domain Controller Authentication certificates for the domain controller.
It can too happen when a domain controller doesn't have a certificate installed for smart cards (Domain Controller or Domain Controller Authentication templates).
0x11 KDC_ERR_TRTYPE_NOSUPP KDC has no support for transited type
0x12 KDC_ERR_CLIENT_REVOKED Clients credentials have been revoked
0x13 KDC_ERR_SERVICE_REVOKED Credentials for server have been revoked
0x14 KDC_ERR_TGT_REVOKED TGT has been revoked
0x15 KDC_ERR_CLIENT_NOTYET Client non notwithstanding valid; try again later on
0x16 KDC_ERR_SERVICE_NOTYET Server not still valid; try over again afterward
0x17 KDC_ERR_KEY_EXPIRED Password has expired—change password to reset The user'southward password has expired.
0x18 KDC_ERR_PREAUTH_FAILED Pre-authentication information was invalid The incorrect password was provided.
0x19 KDC_ERR_PREAUTH_REQUIRED Additional pre-authentication required
0x1a KDC_ERR_SERVER_NOMATCH Requested server and ticket don't match
0x1b KDC_ERR_MUST_USE_USER2USER Server main valid for user2user only
0x1c KDC_ERR_PATH_NOT_ACCEPTED KDC Policy rejects transited path
0x1d KDC_ERR_SVC_UNAVAILABLE A service is not available
0x1f KRB_AP_ERR_BAD_INTEGRITY Integrity bank check on decrypted field failed
0x20 KRB_AP_ERR_TKT_EXPIRED Ticket expired
0x21 KRB_AP_ERR_TKT_NYV Ticket not nonetheless valid
0x22 KRB_AP_ERR_REPEAT Request is a replay
0x23 KRB_AP_ERR_NOT_US The ticket isn't for united states of america
0x24 KRB_AP_ERR_BADMATCH Ticket and authenticator don't match
0x25 KRB_AP_ERR_SKEW Clock skew likewise great
0x26 KRB_AP_ERR_BADADDR Incorrect net address
0x27 KRB_AP_ERR_BADVERSION Protocol version mismatch
0x28 KRB_AP_ERR_MSG_TYPE Invalid msg type
0x29 KRB_AP_ERR_MODIFIED Message stream modified
0x2a KRB_AP_ERR_BADORDER Message out of order
0x2c KRB_AP_ERR_BADKEYVER Specified version of key is not available
0x2d KRB_AP_ERR_NOKEY Service key not bachelor
0x2e KRB_AP_ERR_MUT_FAIL Mutual authentication failed
0x2f KRB_AP_ERR_BADDIRECTION Incorrect message direction
0x30 KRB_AP_ERR_METHOD Alternative authentication method required
0x31 KRB_AP_ERR_BADSEQ Wrong sequence number in message
0x32 KRB_AP_ERR_INAPP_CKSUM Inappropriate type of checksum in message
0x33 KRB_AP_PATH_NOT_ACCEPTED Policy rejects transited path
0x34 KRB_ERR_RESPONSE_TOO_BIG Response too big for UDP; retry with TCP
0x3c KRB_ERR_GENERIC Generic mistake (description in e-text)
0x3d KRB_ERR_FIELD_TOOLONG Field is too long for this implementation
0x3e KDC_ERROR_CLIENT_NOT_TRUSTED Reserved for PKINIT
0x3f KDC_ERROR_KDC_NOT_TRUSTED Reserved for PKINIT
0x40 KDC_ERROR_INVALID_SIG Reserved for PKINIT
0x41 KDC_ERR_KEY_TOO_WEAK Reserved for PKINIT
0x42 KDC_ERR_CERTIFICATE_MISMATCH Reserved for PKINIT
0x43 KRB_AP_ERR_NO_TGT No TGT bachelor to validate USER-TO-USER
0x44 KDC_ERR_WRONG_REALM Reserved for time to come use
0x45 KRB_AP_ERR_USER_TO_USER_REQUIRED Ticket must exist for USER-TO-USER
0x46 KDC_ERR_CANT_VERIFY_CERTIFICATE Reserved for PKINIT
0x47 KDC_ERR_INVALID_CERTIFICATE Reserved for PKINIT
0x48 KDC_ERR_REVOKED_CERTIFICATE Reserved for PKINIT
0x49 KDC_ERR_REVOCATION_STATUS_UNKNOWN Reserved for PKINIT
0x4a KDC_ERR_REVOCATION_STATUS_UNAVAILABLE Reserved for PKINIT
0x4b KDC_ERR_CLIENT_NAME_MISMATCH Reserved for PKINIT
0x4c KDC_ERR_KDC_NAME_MISMATCH Reserved for PKINIT
  • Pre-Hallmark Type [Type = UnicodeString]: the code of pre-Authentication blazon that was used in TGT request.
## Table 5. Kerberos Pre-Hallmark types.
Type Blazon Name Description
0 - Logon without Pre-Authentication.
2 PA-ENC-TIMESTAMP This type is normal for standard password hallmark.
xi PA-ETYPE-INFO The ETYPE-INFO pre-authentication type is sent by the KDC in a KRB-Error indicating a requirement for boosted pre-authentication. Information technology is usually used to notify a client of which key to use for the encryption of an encrypted timestamp for the purposes of sending a PA-ENC-TIMESTAMP pre-authentication value.
Never saw this Pre-Authentication Type in Microsoft Active Directory environment.
fifteen PA-PK-As-REP_OLD Used for Smart Menu logon authentication.
16 PA-PK-Equally-REQ Asking sent to KDC in Smart Carte authentication scenarios.
17 PA-PK-AS-REP This type should too exist used for Smart Card authentication, just in sure Active Directory environments, it is never seen.
19 PA-ETYPE-INFO2 The ETYPE-INFO2 pre-hallmark type is sent past the KDC in a KRB-ERROR indicating a requirement for additional pre-authentication. It is usually used to notify a client of which key to use for the encryption of an encrypted timestamp for the purposes of sending a PA-ENC-TIMESTAMP pre-hallmark value.
Never saw this Pre-Authentication Blazon in Microsoft Active Directory environs.
twenty PA-SVR-REFERRAL-INFO Used in KDC Referrals tickets.
138 PA-ENCRYPTED-Claiming Logon using Kerberos Armoring (FAST). Supported starting from Windows Server 2012 domain controllers and Windows 8 clients.
- This type shows in Audit Failure events.

Certificate Information:

  • Certificate Issuer Proper name [Type = UnicodeString]: the name of Certification Authority that issued smart card document. Populated in Issued by field in certificate. E'er empty for 4771 events.

  • Certificate Serial Number [Type = UnicodeString]: smart card certificate's series number. Can exist constitute in Series number field in the certificate. E'er empty for 4771 events.

  • Certificate Thumbprint [Type = UnicodeString]: smart menu certificate'south thumbprint. Tin exist found in Thumbprint field in the certificate. Always empty for 4771 events.

Security Monitoring Recommendations

For 4771(F): Kerberos pre-hallmark failed.

Type of monitoring required Recommendation
High-value accounts: You lot might take high-value domain or local accounts for which you need to monitor each activeness.
Examples of high-value accounts are database administrators, built-in local ambassador account, domain administrators, service accounts, domain controller accounts so on.		 Monitor this outcome with the "Security ID" that corresponds to the high-value account or accounts.
Anomalies or malicious deportment: Yous might have specific requirements for detecting anomalies or monitoring potential malicious actions. For case, you might need to monitor for use of an account exterior of working hours. When y'all monitor for anomalies or malicious actions, utilise the "Security ID" (with other information) to monitor how or when a particular account is being used.
Non-active accounts: You lot might have non-active, disabled, or guest accounts, or other accounts that should never be used. Monitor this upshot with the "Security ID" that corresponds to the accounts that should never be used.
Business relationship allow list: You might accept a specific allow list of accounts that are the simply ones allowed to perform actions respective to particular events. If this outcome corresponds to a "let list-simply" action, review the "Security ID" for accounts that are outside the let list.
Account naming conventions: Your organization might accept specific naming conventions for account names. Monitor "Subject\Account Name" for names that don't comply with naming conventions.

  • You lot tin runway all 4771 events where the Customer Address is not from your internal IP range or non from private IP ranges.

  • If you lot know that Account Name should be used but from known list of IP addresses, track all Client Address values for this Business relationship Name in 4771 events. If Client Address is not from the let list, generate the alarm.

  • All Client Address = ::1 ways local authentication. If you know the list of accounts that should log on to the domain controllers, then yous need to monitor for all possible violations, where Client Address = ::1 and Account Name is not immune to log on to whatever domain controller.

  • All 4771 events with Customer Port field value > 0 and < 1024 should be examined, because a well-known port was used for outbound connectedness.

  • As well monitor the fields shown in the following table, to notice the issues listed:

Field Issue to find
Pre-Authentication Type Value is not 15 when account must utilise a smart carte du jour for authentication. For more information, see Table 5. Kerberos Pre-Authentication types.
Pre-Authentication Blazon Value is not ii when just standard countersign hallmark is in use in the organization. For more information, meet Table v. Kerberos Pre-Authentication types.
Pre-Authentication Type Value is not 138 when Kerberos Armoring is enabled for all Kerberos communications in the organization. For more data, see Table five. Kerberos Pre-Authentication types.
Failure Code 0x10 (KDC has no support for PADATA blazon (pre-hallmark data)). This error can help you to more than speedily identify smart-card related bug with Kerberos authentication.
Failure Code 0x18 ((Pre-authentication information was invalid), if y'all come across, for example N events in concluding Northward minutes. This consequence can point a brute-force attack on the business relationship password, peculiarly for highly critical accounts.