> For the complete documentation index, see [llms.txt](https://docs.fusion.vectra.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fusion.vectra.ai/detection-models/library/post-compromise/comm_with_malware_internal_external.md).

# comm\_with\_malware\_internal\_external

Explanation The comm\_with\_malware\_internal\_external NDM is designed to detect outbound connections to identified malware command and control (C2) nodes. The NDM triggers when a connection is made to a

**Explanation**

The comm\_with\_malware\_internal\_external NDM is designed to detect outbound connections to identified malware command and control (C2) nodes. The NDM triggers when a connection is made to an IP address that is in the malware\_command\_and\_control Threat Intelligence category and should be treated as a serious event.

**What to Look For**

Internal hosts involved in a comm\_with\_malware\_internal\_external event should be evaluated for malware infections as soon as possible, and isolated from other internal hosts if possible. External hosts should be blocked to prevent other internal infected hosts from communicating with C2 nodes.

**Related MITRE ATT\&CK Categories**

[Command and Control: Application Layer Protocol, Technique T1071 - Enterprise](https://attack.mitre.org/techniques/T1071)

[Command and Control: Non-Application Layer Protocol, Technique T1095 - Enterprise](https://attack.mitre.org/techniques/T1095)

[Command and Control: Non-Standard Port, Technique T1571 - Enterprise](https://attack.mitre.org/techniques/T1571)


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