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Anthropic-Cybersecurity-Skills/skills/analyzing-network-packets-with-scapy/SKILL.md
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Mahipal 2fb6a9faff Rewrite 548 skill descriptions to the activation rubric
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2.4 KiB

name, description, domain, subdomain, tags, version, author, license, nist_csf, mitre_attack
name description domain subdomain tags version author license nist_csf mitre_attack
analyzing-network-packets-with-scapy Use Scapy to craft, send, sniff, and dissect TCP/UDP/ICMP/DNS packets, analyze pcap files, implement SYN scans, and detect anomalous traffic such as fragmented or malformed packets. Use when performing authorized network reconnaissance, protocol-level forensic analysis, or building traffic anomaly detection during security testing. cybersecurity network-security
scapy
packet-analysis
network-forensics
protocol-dissection
pcap
traffic-analysis
1.0 mahipal Apache-2.0
PR.IR-01
DE.CM-01
ID.AM-03
PR.DS-02
T1040
T1071
T1046
T1557

Analyzing Network Packets with Scapy

Overview

Scapy is a Python packet manipulation library that enables crafting, sending, sniffing, and dissecting network packets at granular protocol layers. This skill covers using Scapy for security-relevant tasks including TCP/UDP/ICMP packet crafting, pcap file analysis, protocol field extraction, SYN scan implementation, DNS query analysis, and detecting anomalous traffic patterns such as unusually fragmented packets or malformed headers.

When to Use

  • When investigating security incidents that require analyzing network packets with scapy
  • When building detection rules or threat hunting queries for this domain
  • When SOC analysts need structured procedures for this analysis type
  • When validating security monitoring coverage for related attack techniques

Prerequisites

  • Python 3.8+ with scapy library installed (pip install scapy)
  • Root/administrator privileges for raw socket operations (sniffing, sending)
  • Npcap (Windows) or libpcap (Linux) for packet capture
  • Authorization to perform packet operations on target network

Steps

  1. Read and parse pcap/pcapng files with rdpcap() for offline analysis
  2. Extract protocol layers (IP, TCP, UDP, DNS, HTTP) and field values
  3. Compute traffic statistics: top talkers, protocol distribution, port frequency
  4. Detect SYN flood patterns by analyzing TCP flag ratios
  5. Identify DNS exfiltration indicators via query length and entropy analysis
  6. Craft custom probe packets for authorized network testing
  7. Export findings as structured JSON report

Expected Output

JSON report containing packet statistics, protocol distribution, top source/destination IPs, detected anomalies (SYN floods, DNS tunneling indicators, fragmentation attacks), and per-flow summaries.