analyzing-malicious-pdf-with-peepdf
Perform static analysis of malicious PDF documents using peepdf, pdfid, and pdf-parser to extract embedded JavaScript, shellcode, and suspicious objects.
52
58%
Does it follow best practices?
Impact
—
No eval scenarios have been run
Advisory
Suggest reviewing before use
Optimize this skill with Tessl
npx tessl skill review --optimize ./skills/analyzing-malicious-pdf-with-peepdf/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, specific description that clearly identifies a niche domain (malicious PDF forensic analysis) with concrete tools and actions. Its main weakness is the absence of an explicit 'Use when...' clause, which would help Claude know exactly when to select this skill. The specificity and distinctiveness are excellent.
Suggestions
Add a 'Use when...' clause such as 'Use when the user asks to analyze suspicious or malicious PDFs, investigate PDF-based malware, or extract embedded payloads from PDF documents.'
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions: 'static analysis of malicious PDF documents', 'extract embedded JavaScript, shellcode, and suspicious objects', and names specific tools (peepdf, pdfid, pdf-parser). | 3 / 3 |
Completeness | Clearly answers 'what does this do' (static analysis of malicious PDFs, extracting JavaScript/shellcode/suspicious objects using specific tools), 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 strong natural keywords users would say: 'malicious PDF', 'static analysis', 'JavaScript', 'shellcode', 'suspicious objects', plus specific tool names (peepdf, pdfid, pdf-parser) that users familiar with the domain would reference. | 3 / 3 |
Distinctiveness Conflict Risk | Highly distinctive niche: malicious PDF analysis with specific forensic tools. Very unlikely to conflict with general PDF processing skills or other security-related skills due to the specific tool names and malware analysis focus. | 3 / 3 |
Total | 11 / 12 Passed |
Implementation
35%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill provides a reasonable high-level framework for malicious PDF analysis but critically lacks executable commands and concrete code examples, making it more of a conceptual overview than an actionable skill. The workflow is logically sequenced but missing validation checkpoints and the specific tool invocations that would make it immediately useful. The key concepts and tools tables explain things Claude already knows rather than providing novel, actionable guidance.
Suggestions
Add concrete, executable command examples for each workflow step (e.g., `pdfid.py malicious.pdf`, `peepdf -i malicious.pdf`, `PPDF> object 5`, `PPDF> js_analyse object 5`)
Include a complete worked example showing analysis of a sample malicious PDF from triage through IOC extraction with actual tool output
Add validation checkpoints in the workflow, such as verifying pdfid output before proceeding to interactive analysis, and checking decoded stream validity
Remove the Key Concepts table (Claude knows these) and replace with tool-specific syntax and flags that are harder to recall
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The key concepts table explains PDF-specific terms that Claude likely already knows (e.g., FlateDecode, /OpenAction). The 'When to Use' section is somewhat verbose. The tools table adds marginal value. However, the workflow section is reasonably tight. | 2 / 3 |
Actionability | There are no executable commands or code examples anywhere. The workflow describes steps abstractly ('Open PDF in peepdf interactive mode', 'Dump suspicious streams') without showing actual commands like `peepdf -i malicious.pdf` or `pdfid.py malicious.pdf`. This is entirely descriptive rather than instructive. | 1 / 3 |
Workflow Clarity | The 7-step workflow provides a logical sequence for PDF analysis, but lacks validation checkpoints, error handling, or feedback loops. There's no guidance on what to do if a step fails or produces unexpected results, and no concrete verification steps between stages. | 2 / 3 |
Progressive Disclosure | The content is organized into clear sections with headers and tables, which is good. However, there are no references to external files, and the output format template and key concepts table could be split out. For a skill with no bundle files, the inline organization is adequate but the content is somewhat monolithic. | 2 / 3 |
Total | 7 / 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
0445030
- Reviewed
Table of Contents
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