Deconstruction of an Active Directory integrated certification authority (Enterprise CA)

There are many instructions for setting up and commissioning IT services. However, the associated instructions for decommissioning are usually forgotten.

The following describes how to correctly decommission a certification authority (Enterprise Certification Authority) integrated into Active Directory.

Continue reading „Rückbau einer Active Directory integrierten Zertifizierungsstelle (Enterprise CA)“

Checking the integrity of backups of the certification authority database

Within the framework of the creation of a Backup of a certification authority The question may arise as to how to ensure that the integrity of the certification authority database backup is guaranteed so that it can be properly restored can be.

The Certification Authority database is available in a Microsoft JET Blue database engine (also known as Extensible Storage Engine, ESE). Their working and backup files have the extension .edb and can be created with the operating system tool esentutl be managed.

Continue reading „Prüfen der Integrität von Sicherungen der Zertifizierungsstellen-Datenbank“

The database schema of the Certification Authority database

Would you like to Queries against the Certification Authority database formulate, you must first know what you want to look for.

There is a possibility to output the database schema of the certification authority database.

Continue reading „Das Datenbankschema der Zertifizierungsstellen-Datenbank“

Limits of Microsoft Active Directory Certificate Services

Active Directory Certificate Services have existed (albeit under a different name) in their basic form since Windows NT 4.0. The architecture based on Active Directory used today was introduced with Windows 2000 Server. AD CS are very well integrated into the Windows ecosystem and continue to be very popular in enterprises and government agencies of all sizes worldwide.

People like to point out the many possibilities offered by Active Directory Certificate Services. Rarely, however, is reference made to what can be done with them. not is possible. In the meantime, the product has also reached its limits in many places.

What these are will be explained in more detail below in order to better decide whether the AD CS can be the right solution for planned projects.

Continue reading „Grenzen der Microsoft Active Directory Certificate Services“

Establish a mapping from a user certificate to the associated computer

Assume the following scenario:

  • A user's computer is stolen or infected with malware.
  • The integrity of certificates located on the computer can no longer be guaranteed.
  • The certificates of the user(s) that were requested on this computer must be revoked.
  • However, one would like to avoid revoking all certificates of a user.
  • Thus, a connection must be established between the user's certificates and the computer on which they were requested.

If the certificates were issued by Autoenrollment requested, we can take advantage of the fact that a corresponding attribute was part of the original certificate request, and that the certificate request is stored in the certificate authority database along with the certificate.

Continue reading „Eine Zuordnung von einem Benutzerzertifikat zum dazugehörigen Computer herstellen“

Restoring certificates from the SMTP Exit Module data

If you restore a certification authority from a backup after a disaster has occurred, you will probably find that certificates were issued in the period between the last backup and the system failure with corresponding data loss.

These certificates are now not stored in the restored certificate authority database, so they cannot be restored if needed.

If you are using the SMTP Exit Module, you can at least determine the serial numbers of the certificates from the sent e-mails and revoke them.

Continue reading „Wiederherstellen von Zertifikaten aus den Daten des SMTP Exit Moduls“

Moving the certification authority database to another directory or drive

In the operation of a certification authority, one may find that it is necessary to subsequently change the storage path for the certification authority database. For example, one may want to move the database to another partition/drive.

Continue reading „Verschieben der Zertifizierungsstellen-Datenbank in ein anderes Verzeichnis oder auf ein anderes Laufwerk“

Certificate or revocation list issuance fails with error code CERTSRV_E_NO_DB_SESSIONS

Assume the following scenario:

  • The Certification Authority cannot issue certificates and/or
  • The Certification Authority cannot issue revocation lists.
  • At least one of the following error messages is logged:

Event ID: 53 (Microsoft-Windows-CertificationAuthority)

Active Directory Certificate Services denied request 12345 because An attempt was made to open a Certification Authority database session, but there are already too many active sessions. The server may need to be configured to allow additional sessions. 0x8009400f (-2146877425 CERTSRV_E_NO_DB_SESSIONS). The request was for CN=Rudi Ratlos. Additional information: Denied by Policy Module

Event ID: 130 (Microsoft-Windows-CertificationAuthority)

Active Directory Certificate Services could not create a certificate revocation list. An attempt was made to open a Certification Authority database session, but there are already too many active sessions. The server may need to be configured to allow additional sessions 0x8009400f (-2146877425). This may cause applications that need to check the revocation status of certificates issued by this CA to fail. You can recreate the certificate revocation list manually by running the following command: "certutil -CRL". If the problem persists, restart Certificate Services.
Continue reading „Die Ausstellung von Zertifikaten oder Sperrlisten schlägt fehl mit Fehlercode CERTSRV_E_NO_DB_SESSIONS“

The display name of a certificate template is not resolved. Only the object identifier (OID) of the certificate template is displayed.

Assume the following scenario:

  • For a certificate template, only the object identifier is shown, but not the display name and/or
  • Queries against the certificate authority database contain only the object identifier for the certificate template ("CertificateTemplate" field), but not the display name.
Continue reading „Der Anzeigename einer Zertifikatvorlage wird nicht aufgelöst. Es wird nur der Objektidentifizierer (OID) der Zertifikatvorlage angezeigt.“

Details of the event with ID 4880 of the source Microsoft-Windows-Security-Auditing

Event Source:Microsoft Windows Security Auditing
Event ID:4880 (0x1310)
Event log:Security
Event type:Information
Event text (English):Certificate Services started. Certificate Database Hash: %1 Private Key Usage Count: %2 CA Certificate Hash: %3 CA Public Key Hash: %4
Event text (German):The certificate services have been started. Certificate database hash: %1 Private key usage count: %2 Certification authority hash: %3 Certification authority public key hash: %4
Continue reading „Details zum Ereignis mit ID 4880 der Quelle Microsoft-Windows-Security-Auditing“

Performance problems with auditing of "Start and stop Active Directory Certificate Services".

When configuring the auditing settings of a certificate authority, one is inclined to select the "Start and Stop Active Directory Certificate Services" option. However, this option may cause problems in some circumstances.

Continue reading „Performanceprobleme bei Auditierung von „Start and stop Active Directory Certificate Services““

More than one common name (CN) in the certificate

Nowadays rather a curiosity than really relevant in practice, but it does happen from time to time that you receive certificate requests that contain more than one common name in the subject. Even though it may seem surprising, this is quite possible and also RFC compliant.

Continue reading „Mehr als ein gemeinsamer Name (Common Name, CN) im Zertifikat“

Restoring a certification authority from backup

The following describes how to restore a certification authority from backup. In addition to the disaster case, this procedure is also part of the Migration of a certification authority to a new server.

Continue reading „Wiederherstellung einer Zertifizierungsstelle aus der Sicherung (Backup)“

Queries against the certificate authority database fail with error message "0x80070005 (WIN32: 5 ERROR_ACCESS_DENIED)".

Assume the following scenario:

  • One runs a query against the certification authority database.
  • The query fails with the following error message:
CertUtil: -view command FAILED: 0x80070005 (WIN32: 5 ERROR_ACCESS_DENIED)
Continue reading „Abfragen gegen die Zertifizierungsstellen-Datenbank schlagen fehl mit Fehlermeldung „0x80070005 (WIN32: 5 ERROR_ACCESS_DENIED)““

(Mass) deletion of entries in the certification authority database (certificates, requirements, revocation lists)

Sometimes it happens that the database of the certification authority becomes extremely large. Perhaps a large number of certificate requests have arrived unnoticed and have been rejected, or perhaps there are many certificates in the database that have been issued twice. Before the certification authority database compacts can be used, these entries must first be deleted in order to free up the storage space in the database.

Continue reading „(Massenhaftes) Löschen von Einträgen in der Zertifizierungsstellen-Datenbank (Zertifikate, Anforderungen, Sperrlisten)“