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analyzing-uefi-bootkit-persistence

Analyzes UEFI bootkit persistence mechanisms including firmware implants in SPI flash, EFI System Partition (ESP) modifications, Secure Boot bypass techniques, and UEFI variable manipulation. Covers detection of known bootkit families (BlackLotus, LoJax, MosaicRegressor, MoonBounce, CosmicStrand), ESP partition forensic inspection, chipsec-based firmware integrity verification, and Secure Boot configuration auditing. Activates for requests involving UEFI malware analysis, firmware persistence investigation, boot chain integrity verification, or Secure Boot bypass detection.

90

Quality

88%

Does it follow best practices?

Impact

Pending

No eval scenarios have been run

SecuritybySnyk

Advisory

Suggest reviewing before use

SKILL.md
Quality
Evals
Security

Quality

Discovery

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.

This is an excellent skill description that thoroughly covers specific capabilities, includes rich domain-appropriate trigger terms, explicitly states both what the skill does and when it should activate, and occupies a clearly distinct niche. It uses proper third-person voice throughout and avoids vague language or buzzwords. The inclusion of specific tool names (chipsec) and malware family names further strengthens its precision and trigger quality.

DimensionReasoningScore

Specificity

Lists multiple specific concrete actions: analyzing firmware implants in SPI flash, ESP modifications, Secure Boot bypass techniques, UEFI variable manipulation, detection of named bootkit families, ESP partition forensic inspection, chipsec-based firmware integrity verification, and Secure Boot configuration auditing.

3 / 3

Completeness

Clearly answers both 'what' (analyzes UEFI bootkit persistence mechanisms, covers detection of known families, ESP forensic inspection, chipsec verification, Secure Boot auditing) and 'when' with explicit triggers ('Activates for requests involving UEFI malware analysis, firmware persistence investigation, boot chain integrity verification, or Secure Boot bypass detection').

3 / 3

Trigger Term Quality

Excellent coverage of natural terms a security analyst would use: 'UEFI', 'bootkit', 'firmware', 'SPI flash', 'ESP', 'Secure Boot', specific malware family names (BlackLotus, LoJax, MosaicRegressor, MoonBounce, CosmicStrand), 'chipsec', 'boot chain integrity', 'firmware persistence'. These are precisely the terms a user investigating UEFI threats would mention.

3 / 3

Distinctiveness Conflict Risk

Highly distinctive niche focused specifically on UEFI/firmware-level threats and boot chain security. The named bootkit families, SPI flash, ESP partition forensics, and chipsec references make it extremely unlikely to conflict with general malware analysis or other security skills.

3 / 3

Total

12

/

12

Passed

Implementation

77%

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

This is a strong, highly actionable skill with excellent workflow clarity and real executable commands covering the full UEFI bootkit analysis pipeline. Its main weaknesses are moderate verbosity from definitional content Claude doesn't need (Key Concepts table, Tools descriptions) and a monolithic structure that would benefit from splitting reference material into separate files. The detailed output format example and realistic scenario are particularly valuable additions.

Suggestions

Remove or significantly trim the Key Concepts table and Tools & Systems section - Claude already knows what SPI flash, Secure Boot, YARA, and chipsec are; keep only non-obvious project-specific details.

Move the detailed output format example and common scenarios into separate referenced files (e.g., OUTPUT_FORMAT.md, SCENARIOS.md) to reduce the main skill's token footprint.

DimensionReasoningScore

Conciseness

The skill is fairly comprehensive but includes some unnecessary verbosity, particularly the Key Concepts table which defines terms Claude already knows (e.g., what SPI Flash is, what Secure Boot is, what YARA is). The Tools & Systems section also largely restates information already evident from the workflow commands. However, the workflow steps themselves are reasonably efficient.

2 / 3

Actionability

The skill provides fully executable commands throughout all workflow steps - specific chipsec commands, flashrom invocations, find/grep pipelines, sigcheck usage, and Volatility commands. Commands are copy-paste ready with real tool syntax and actual UEFI variable GUIDs.

3 / 3

Workflow Clarity

The 7-step workflow is clearly sequenced from acquisition (SPI dump) through analysis to reporting. Validation checkpoints are present throughout - hash verification of dumps, whitelist comparison, signature verification, and the explicit instruction to boot from trusted media before analysis. The scenario section includes pitfalls that serve as error-prevention guidance.

3 / 3

Progressive Disclosure

The content is entirely self-contained in a single monolithic file with no references to external files for detailed content. The Key Concepts table, Tools & Systems section, and the extensive output format example could be split into separate reference files. For a skill of this length (~200+ lines), better progressive disclosure would improve navigability.

2 / 3

Total

10

/

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.

Validation10 / 11 Passed

Validation for skill structure

CriteriaDescriptionResult

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

Total

10

/

11

Passed

Repository
mukul975/Anthropic-Cybersecurity-Skills
Reviewed

Table of Contents

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