> 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/informational/tcpfrag.md).

# tcpfrag

**Explanation**

This event is designed to detect a TCP fragmentation flood on the network. TCP fragmentation occurs when a large data packet is divided into smaller packets for transmission across the network. This can be used as a method of attack to flood a network with large volumes of fragmented packets, causing network congestion and denial of service.

**What to Look For**

If this event is triggered, it is important to examine the network traffic for signs of a TCP fragmentation flood. This can be identified by analyzing the TCP packets for fragmentation flags and identifying packets with the same identification number. It is also important to examine the endpoint behavior to determine if any systems are experiencing high CPU or memory usage, which can be a sign of network congestion. Remediation efforts will involve identifying the source of the flood and blocking the attack at the network level.

**Related MITRE ATT\&CK Categories**

[Impact: Network Denial of Service, Technique T1498 - Enterprise](https://attack.mitre.org/techniques/T1498)

[Impact: Endpoint Denial of Service, Technique T1499 - Enterprise](https://attack.mitre.org/techniques/T1499)


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