# 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) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.fusion.vectra.ai/detection-models/library/informational/tcpfrag.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.