> 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/reconnaissance/connscan_external_internal.md).

# connscan\_external\_internal

**Explanation**

The connscan\_external\_internal NDM detects connection scanning attempts hitting the customer's network from the Internet. It does this by monitoring for a high rate of aborted successful TCP connections, which may indicate an attacker attempting to discover available services or potential vulnerabilities on the network edge. The NDM triggers when it detects a threshold of connections to different services within a certain time period.

**What to Look For**

Scanning activity on the Internet is quite commonplace. If there are unexpected services exposed to the Internet, check firewall or other blocking rules to prevent unwanted exposure.

**Related MITRE ATT\&CK Categories**

[Reconnaissance: Active Scanning, Technique T1595 - Enterprise](https://attack.mitre.org/techniques/T1595)


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