analyzing-command-and-control-communication

Analyzes malware command-and-control (C2) communication protocols to understand beacon patterns, command structures, data encoding, and infrastructure. Covers HTTP, HTTPS, DNS, and custom protocol C2 analysis for detection development and threat intelligence. Activates for requests involving C2 analysis, beacon detection, C2 protocol reverse engineering, or command-and-control infrastructure mapping.

Quality

—

Does it follow best practices?

Impact

—

No eval scenarios have been run

Securityby

Advisory

Suggest reviewing before use

Quality

Content

65%

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The skill is highly actionable with executable code throughout and a clear six-step workflow, but it is held back by verbosity (the Key Concepts table), absent validation checkpoints, and a monolithic structure that ignores its own bundle files. Tightening inline reference material and linking the existing api-reference.md and agent.py would lift conciseness and progressive disclosure.

Suggestions

Add explicit validation/verification checkpoints to the workflow — e.g., after Step 3 confirm the decoded command set against Ghidra disassembly, and after Step 6 test Suricata rules against the source PCAP before finalizing.

Reference the existing bundle files from the body (references/api-reference.md for scapy/dpkt/tshark/JA3 API detail, scripts/agent.py for the beacon-detection implementation) instead of inlining all of that material.

Trim the Key Concepts table to only C2-specific, non-obvious definitions and consider moving the framework-signature and Tools & Systems tables into a reference file to reduce the inline token load.

Dimension	Reasoning	Score
Conciseness	The body is mostly efficient operational code, but the 'Key Concepts' table explains largely known terms (beaconing, jitter, malleable C2, domain fronting) and inline reference material could be tightened; not the lean level-3 ideal yet above verbose level 1.	2 / 3
Actionability	Provides fully executable, copy-paste-ready code (scapy beacon analysis, dpkt HTTP decoding, requests-based Shodan/VirusTotal enrichment, CobaltStrikeParser usage, and complete Suricata rules), matching the executable-and-complete anchor.	3 / 3
Workflow Clarity	Steps 1–6 are clearly sequenced and a numbered scenario approach exists, but there are no explicit validation/verification checkpoints (e.g., confirming a decoded protocol against disassembly or verifying a signature fires), so it sits at the sequence-present-but-checkpoints-implicit level rather than level 3.	2 / 3
Progressive Disclosure	Sections are reasonably organized, but the ~370-line body is a monolithic wall with content that belongs in references, and the existing bundle files (references/api-reference.md, scripts/agent.py) are never referenced from the body — references present but not clearly signaled.	2 / 3
	Total	9 / 12 Passed

Description

100%

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

The description is strong: third-person voice, concrete capability actions, natural trigger terms, and an explicit activation clause covering both what and when. It is well-scoped to the C2 analysis niche with low conflict risk.

Dimension	Reasoning	Score
Specificity	Lists multiple concrete actions: 'understand beacon patterns, command structures, data encoding, and infrastructure' and 'detection development and threat intelligence', matching the multiple-specific-actions anchor rather than the domain-only level 2.	3 / 3
Completeness	Explicitly states what it does ('Analyzes malware command-and-control (C2) communication protocols...') and when to use it ('Activates for requests involving...'), clearly answering both what and when with explicit triggers.	3 / 3
Trigger Term Quality	Uses natural terms a user would say — 'C2 analysis, beacon detection, C2 protocol reverse engineering, or command-and-control infrastructure mapping' plus 'HTTP, HTTPS, DNS' — giving good coverage rather than only some relevant keywords.	3 / 3
Distinctiveness Conflict Risk	The C2/malware-analysis niche with distinct triggers (beacon detection, C2 protocol reverse engineering, infrastructure mapping) is unlikely to overlap with unrelated skills; it is clearly distinguishable rather than merely somewhat specific.	3 / 3
	Total	12 / 12 Passed

Validation

93%

Warnings & errors only

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 15 / 16 Passed

Validation for skill structure

Criteria	Description	Result
frontmatter_unknown_keys	Unknown frontmatter key(s) found; consider removing or moving to metadata	Warning

	Total	15 / 16 Passed

Repository: mukul975/Anthropic-Cybersecurity-Skills
Commit: 673da1f

Reviewed: 13 days ago

Table of Contents

Discovery Implementation Validation

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.