Querying and deleting certificate requests from an AD CS database

Certificate request information in an AD CS database is stored in 3 different tables The glue between those 3 tables is the RequestID in the Default table, that corresponds to the AttributeRequestID column in the Attrib table and the ExtensionRequestID column in the Ext table.

Whenever a certutil -view command is issued, it will default to the Default table, querying the Attrib and Ext tables requires them to be specified, e.g.:

certutil -view Attrib

will dump the content of the Attrib table


and

certutil -view Ext

will dump the content of the Ext table


Remember that certutil [Options], such as restrict and out, which can be used to filter the output of the queries above, must always be present before the -view command:

certutil [Options] -view

The default usage of certutil -view without specifying the table extracts data from the Default table, but it also includes the data contained in the Attrib and Ext tables, presenting it altogether in a convenient format.

if we query for a particular RequestID:

Note that the output includes a "Request Attributes" and a "Certificate Extensions". The information contained there is retrieved from the Attrib and Ext tables, which can also be queried separately:


So querying via certutil for a particular request without specifying any table will return the data contained for that particular request in all 3 tables (Default, Attrib and Ext).

Similarly, when a database row is deleted, using the -deleterow certutil command without specifying the table but just the RequestID, data will be deleted from all 3 tables:


In summary, when using certutil without specifying the database table to query or delete individual requests based on their RequestID, the command will return or delete data from all 3 tables that contain certificate request data in the AD CS database: Default, Attrib and Ext.

Comments

Post a Comment

Popular posts from this blog

Decoding OCSP GET requests

Many clients default to OCSP requests via HTTP GET, encoding the request details as part of the URL. These kind of requests can be found in the logs: http://ocsp.ekaitza.net/ocsp/MFQwUjBQME4wTDAJBgUrDgMCGgUABBQ1uvBCJo3G3TPBvK%2BGVqszOaLAawQUb38ZjesMwNeYLEzdGvP%2FZi9TlkACE3cAEdYaIhMmuymSdxoAAAAR1ho%3D As per RFC 6960 , the request is constructed as: GET {url}/{url-encoding of base-64 encoding of the DER encoding of the OCSPRequest} So in order to find out the details of the request we have to: 1. Remove the URL encoding This can be done with different tools, depending on the OS/platform being used.Given the input above: MFQwUjBQME4wTDAJBgUrDgMCGgUABBQ1uvBCJo3G3TPBvK%2BGVqszOaLAawQUb38ZjesMwNeYLEzdGvP%2FZi9TlkACE3cAEdYaIhMmuymSdxoAAAAR1ho%3D the output would be: MFQwUjBQME4wTDAJBgUrDgMCGgUABBQ1uvBCJo3G3TPBvK+GVqszOaLAawQUb38ZjesMwNeYLEzdGvP/Zi9TlkACE3cAEdYaIhMmuymSdxoAAAAR1ho= We can then create a text file with it, e.g.:  $ echo "MFQwUjBQME4wTDAJBgUrDgMCGgUABBQ1uvBCJo3G3TPBvK+GVqsz
Read more

Signing a CSR with an Enrollment Agent certificate

Image
Often certificate templates in AD CS are configured to require a set of authorised signatures for issuance: This is useful e.g. when issuance approval is delegated to a component outside of AD CS roles, such as some CA management or registration authority portal software. Combined with the template security settings this can prevent requests from being raised directly from the CA without going through a custom standard request process, and depending on the level of security required, multiple signatures can be enforced and optionally also additional CA certificate manager approval. In order to produce each of this signatures an "Enrollment Agent" certificate is used, a certificate with the "Certificate Request Agent (1.3.6.1.4.1.311.20.2.1)"  Enhanced Key Usage. Sometimes it is required to raise requests directly towards the CA, e.g. using the RPC/DCOM interface from the command line, but it is not desirable and/or possible to change the template configuration, so t
Read more

Compacting an AD CS database

Given the healthy trend towards decreasing certificate validity periods, it is very likely that the size of an AD CS Certification Authority database will grow following that same trend. Despite regular maintenance activities including deletion of records such as failed, denied etc. it could be that at some point the CA database reaches a problematic size. Deleting records from an AD CS CA database will internally free up the space previously occupied by those records but will not decrease the size of the database file itself. I.e. new records will reuse the freed up space but the total space used by the database file will not decrease. This helps keeping the database size under control but does not help if the size had already increased over acceptable limits; in this case the database must be compacted. The CA is often a critical resource, so it is recommended to keep various backups of different nature, to try to make sure we can recover it in case something goes wrong. Here a
Read more