> 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 | Requires one of the following data sources:
Palo Alto Networks Firewall EAL Logs OR XDR Agent
|
| 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
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
**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.
---
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