The following analytic identifies when a new certificate is requested against the Certificate Services - AD CS. By its very nature this is not malicious, but should be tracked and correlated with other events related to certificate requests. When an account requests a certificate, the CA generates event ID (EID) 4886 "Certificate Services received a certificate request".
- Type: Anomaly
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2023-02-06
- Author: Michael Haag, Splunk
- ID: 747d7800-2eaa-422d-b994-04d8bb9e06d0
Kill Chain Phase
- CIS 10
1 2 3 4 5 `wineventlog_security` EventCode=4886 | stats count min(_time) as firstTime max(_time) as lastTime by dest, name, Requester, action, Attributes | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_steal_authentication_certificates_certificate_request_filter`
The SPL above uses the following Macros:
windows_steal_authentication_certificates_certificate_request_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
To implement this analytic, enhanced Audit Logging must be enabled on AD CS and within Group Policy Management for CS server. See Page 115 of first reference.
Known False Positives
False positives will be generated based on normal certificate requests. Leave enabled to generate Risk, as this is meant to be an anomaly analytic.
Associated Analytic Story
|8.0||10||80||A certificate was requested by $dest$.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 1