> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/analytics-alerts/alerts-by-name/possible-kerberos-user-enumeration.md).

# Possible Kerberos User Enumeration

### Synopsis

| Field                | Value                                         |
| -------------------- | --------------------------------------------- |
| Activation Period    | 14 Days                                       |
| Training Period      | 30 Days                                       |
| Test Period          | 10 Minutes                                    |
| Deduplication Period | 1 Day                                         |
| Required Data        | XDR Agent with eXtended Threat Hunting (XTH)  |
| Detection Modules    | Identity Analytics                            |
| ATT\&CK Tactic       | Discovery (TA0007)                            |
| ATT\&CK Technique    | Account Discovery: Domain Account (T1087.002) |
| Severity             | Informational                                 |

### Description

Multiple Kerberos TGT requests with KDC\_ERR\_C\_PRINCIPAL\_UNKNOWN errors were generated on different users in the last 10 minutes which may indicate Kerberos user enumeration.

### Attacker's Goals

The attacker may attempt to gain an initial foothold in the domain by enumerating users.

### Investigative actions

* Identify the source host from which the failed logons originated, by making sure the IP is not a shared address.
* Check the host from which the errors originated, and verify the legitimacy of the TGT requests.
* Correlate successful logons from the source host to identify potential account compromises following the failed attempts.
* Review source host activity to detect any additional suspicious or lateral movement behavior.

### Variations

<details>

<summary>Possible Kerberos User Enumeration Involving Exposed Users</summary>

**Synopsis**

| Field             | Value                                         |
| ----------------- | --------------------------------------------- |
| ATT\&CK Tactic    | Discovery (TA0007)                            |
| ATT\&CK Technique | Account Discovery: Domain Account (T1087.002) |
| Severity          | Low                                           |

**Description**

Multiple Kerberos TGT requests with KDC\_ERR\_C\_PRINCIPAL\_UNKNOWN errors were generated on different users in the last 10 minutes which may indicate Kerberos user enumeration.

**Attacker's Goals**

The attacker may attempt to gain an initial foothold in the domain by enumerating users.

**Investigative actions**

* Identify the source host from which the failed logons originated, by making sure the IP is not a shared address.
* Check the host from which the errors originated, and verify the legitimacy of the TGT requests.
* Correlate successful logons from the source host to identify potential account compromises following the failed attempts.
* Review source host activity to detect any additional suspicious or lateral movement behavior.

</details>


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