> 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/abnormal-network-communication-with-a-rare-combination-of-http-user-agent-and-http-server.md).

# Abnormal network communication with a rare combination of HTTP User Agent and HTTP Server

### Synopsis

| Field                | Value                                                                                                   |
| -------------------- | ------------------------------------------------------------------------------------------------------- |
| Activation Period    | 14 Days                                                                                                 |
| Training Period      | 30 Days                                                                                                 |
| Test Period          | N/A (single event)                                                                                      |
| Deduplication Period | 1 Day                                                                                                   |
| Required Data        | <p>Requires one of the following data sources:<br>Palo Alto Networks Firewall EAL Logs OR XDR Agent</p> |
| ATT\&CK Tactic       | Command and Control (TA0011), Exfiltration (TA0010)                                                     |
| ATT\&CK Technique    | Web Service (T1102), Exfiltration Over Web Service (T1567)                                              |
| Severity             | Informational                                                                                           |

### Description

Abnormal network communication with a rare combination of HTTP User Agent and HTTP Server to an external address.

### Attacker's Goals

* Data exfiltration, attack tool staging or command and control channel through a trusted service.

### Investigative actions

* Examine the legitimacy of the application that produced this rare combination of HTTP User Agent with the external HTTP Server.
* Examine the parent process of this application.
* Check for anomalies at the time when the communication occurred.

### Variations

<details>

<summary>Abnormal network communication with a rare combination of HTTP User Agent and HTTP Server where both the User Agent and the HTTP Server are rare</summary>

**Synopsis**

| Field             | Value                                                      |
| ----------------- | ---------------------------------------------------------- |
| ATT\&CK Tactic    | Command and Control (TA0011), Exfiltration (TA0010)        |
| ATT\&CK Technique | Web Service (T1102), Exfiltration Over Web Service (T1567) |
| Severity          | Low                                                        |

**Description**

Abnormal network communication with a rare combination of HTTP User Agent and HTTP Server to an external address.

**Attacker's Goals**

* Data exfiltration, attack tool staging or command and control channel through a trusted service.

**Investigative actions**

* Examine the legitimacy of the application that produced this rare combination of HTTP User Agent with the external HTTP Server.
* Examine the parent process of this application.
* Check for anomalies at the time when the communication occurred.

</details>


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