analyzing-cobalt-strike-beacon-configuration
Extract and analyze Cobalt Strike beacon configuration from PE files and memory dumps to identify C2 infrastructure, malleable profiles, and operator tradecraft.
57
66%
Does it follow best practices?
Impact
—
No eval scenarios have been run
Critical
Do not install without reviewing
Optimize this skill with Tessl
npx tessl skill review --optimize ./skills/analyzing-cobalt-strike-beacon-configuration/SKILL.mdQuality
Discovery
82%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This is a strong, domain-specific description with excellent specificity and trigger term coverage for its niche audience of threat intelligence and incident response analysts. Its main weakness is the absence of an explicit 'Use when...' clause, which would help Claude know precisely when to select this skill. The technical terminology is appropriate and distinctive for this specialized domain.
Suggestions
Add an explicit 'Use when...' clause, e.g., 'Use when the user asks about Cobalt Strike beacons, C2 analysis, beacon parsing, or needs to extract configuration from suspicious PE files or memory dumps.'
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions: 'Extract and analyze beacon configuration', 'identify C2 infrastructure, malleable profiles, and operator tradecraft' from specific input types 'PE files and memory dumps'. | 3 / 3 |
Completeness | Clearly answers 'what does this do' (extract and analyze Cobalt Strike beacon configuration to identify C2 infrastructure, malleable profiles, and tradecraft), but lacks an explicit 'Use when...' clause or equivalent trigger guidance, which caps this at 2 per the rubric. | 2 / 3 |
Trigger Term Quality | Includes highly relevant natural keywords a security analyst would use: 'Cobalt Strike', 'beacon', 'configuration', 'PE files', 'memory dumps', 'C2 infrastructure', 'malleable profiles', 'operator tradecraft'. These are the exact terms someone working in this domain would mention. | 3 / 3 |
Distinctiveness Conflict Risk | Extremely specific niche — Cobalt Strike beacon analysis is a very distinct domain that would not overlap with other skills. The combination of 'Cobalt Strike', 'beacon configuration', 'C2 infrastructure', and 'malleable profiles' creates a unique fingerprint. | 3 / 3 |
Total | 11 / 12 Passed |
Implementation
50%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
The skill excels in actionability with fully executable, well-structured Python code covering the complete beacon analysis workflow from extraction through network signature generation. However, it is significantly verbose—spending many tokens on background concepts Claude already knows (Cobalt Strike overview, TLV format explanation, malleable C2 profile descriptions) and generic 'When to Use' boilerplate. The workflow would benefit from explicit validation checkpoints between steps and better progressive disclosure by offloading code into bundle files.
Suggestions
Remove or drastically reduce the Overview, Key Concepts, and 'When to Use' sections—Claude knows what Cobalt Strike is and what TLV encoding means. Keep only the specific technical details Claude wouldn't know (XOR keys 0x69/0x2e, config size 4096 bytes, specific TLV type IDs).
Add explicit validation checkpoints within the workflow, e.g., after Step 1 verify config was found before proceeding, after Step 2 cross-check manual results against automated extraction, after Step 3 confirm YARA matches before generating network signatures.
Move the large code blocks into separate bundle files (e.g., extract_config.py, manual_decrypt.py, yara_rules.py) and reference them from SKILL.md with brief descriptions of what each does.
Remove the generic 'When to Use' section entirely—it adds no actionable information beyond what the skill title already conveys.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill is excessively verbose. The Overview, Key Concepts, and Prerequisites sections explain concepts Claude already knows (what Cobalt Strike is, what TLV means, what malleable C2 profiles are, what watermarks do). The 'When to Use' section is generic boilerplate. The code examples are extensive but include many comments and print statements that add bulk without proportional value. This could be cut by 40-50% without losing actionable content. | 1 / 3 |
Actionability | The skill provides fully executable Python code across four steps: automated extraction with dissect.cobaltstrike, manual XOR decryption with TLV parsing, YARA rule compilation and scanning, and network signature generation. Code is copy-paste ready with proper imports, function signatures, and real field mappings (TLV type IDs, XOR keys, config offsets). | 3 / 3 |
Workflow Clarity | The four steps are clearly sequenced and logically ordered (extract → manual decrypt → detect → correlate). However, there are no explicit validation checkpoints or feedback loops between steps. The 'Validation Criteria' section lists expected outcomes but doesn't integrate them into the workflow as verification gates. For a security analysis workflow where incorrect extraction could lead to wrong attribution, inline validation steps are important. | 2 / 3 |
Progressive Disclosure | The content is a monolithic wall of text with all code inline. The four substantial code blocks (each 30-80 lines) could be split into separate referenced files. The References section provides external links but there are no bundle files to offload detailed content. The structure has clear headings but the sheer volume of inline code hurts navigability. | 2 / 3 |
Total | 8 / 12 Passed |
Validation
90%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 10 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
Total | 10 / 11 Passed | |
- Repository
- mukul975/Anthropic-Cybersecurity-Skills
- Commit
0f429d0
- Reviewed
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