> 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/multiple-users-authenticated-with-weak-ntlm-to-a-host.md).

# Multiple users authenticated with weak NTLM to a host

### Synopsis

| Field                | Value                                         |
| -------------------- | --------------------------------------------- |
| Activation Period    | 14 Days                                       |
| Training Period      | 30 Days                                       |
| Test Period          | 1 Hour                                        |
| Deduplication Period | 1 Day                                         |
| Required Data        | XDR Agent                                     |
| Detection Modules    | Identity Analytics                            |
| ATT\&CK Tactic       | Lateral Movement (TA0008)                     |
| ATT\&CK Technique    | Use Alternate Authentication Material (T1550) |
| Severity             | Informational                                 |

### Description

Multiple user accounts authenticated to a host via NTLMv1 or LM authentication for the first time in the past 30 days. This may be a result of an NTLM downgrade attack A downgrade attack may force the client to authenticate with a weaker hash/protocol (such as NTLMv1 or even LM) instead of NTLMv2.

### Attacker's Goals

The attacker attempts to gain access to the accounts.

### Investigative actions

* Audit all login events with a weaker protocol and review any anomalous usage.
* Investigate the mentioned host for additional suspicious activity.


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