analyzing-malicious-pdf-with-peepdf

analyzing-malicious-pdf-with-peepdf is a skill for Claude Code, Codex from Youngmaidainon/Agent-Level-Up. It costs 73 tokens per session (803 once invoked), scanned A, a copy of analyzing-malicious-pdf-with-peepdf, MIT.

A procedure for examining suspicious PDF files without opening them normally. It uses peepdf, pdfid, and pdf-parser to find embedded JavaScript, shellcode, executables, and other suspicious objects.

In plain words
What is it for?
Triaging phishing attachments, exploring PDF structure, extracting and decoding embedded data, analyzing JavaScript or shellcode, and creating detection signatures.
Why use it?
It helps investigators inspect a potentially harmful document while reducing the risk of executing its contents.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Triaging phishing attachments, exploring PDF structure, extracting and decoding embedded data, analyzing JavaScript or shellcode, and creating detection signatures.

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Install with agentmods
npx agentmods add skills/youngmaidainon/agent-level-up/analyzing-malicious-pdf-with-peepdf
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Youngmaidainon/Agent-Level-Up --skill analyzing-malicious-pdf-with-peepdf
Clone the repo
git clone --depth 1 https://github.com/Youngmaidainon/Agent-Level-Up

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for analyzing-malicious-pdf-with-peepdf

README.md
[![agentmods](https://agentmods.dev/badge/skills/youngmaidainon/agent-level-up/analyzing-malicious-pdf-with-peepdf/github.svg)](https://agentmods.dev/skills/youngmaidainon/agent-level-up/analyzing-malicious-pdf-with-peepdf)
Your own site
<a href="https://agentmods.dev/skills/youngmaidainon/agent-level-up/analyzing-malicious-pdf-with-peepdf"><img src="https://agentmods.dev/badge/skills/youngmaidainon/agent-level-up/analyzing-malicious-pdf-with-peepdf/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for analyzing-malicious-pdf-with-peepdf

Your own site · 80×15
<a href="https://agentmods.dev/skills/youngmaidainon/agent-level-up/analyzing-malicious-pdf-with-peepdf"><img src="https://agentmods.dev/badge/skills/youngmaidainon/agent-level-up/analyzing-malicious-pdf-with-peepdf.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 803 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00073 $0.00803
Opus 5 $0.00036 $0.00402
Sonnet 5 $0.00015 $0.00161
Haiku 4.5 $0.00007 $0.00080

Measured 10d ago against content hash 7cdd9a208444, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

analyzing-malicious-pdf-with-peepdf scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/agent.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to analyzing-malicious-pdf-with-peepdf — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

cyber-security/ctf/analyzing-malicious-pdf-with-peepdf/SKILL.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Analyzing Malicious PDF with peepdf

When to Use

  • When triaging suspicious PDF attachments from phishing emails
  • During malware analysis of PDF-based exploit documents
  • When extracting embedded JavaScript, shellcode, or executables from PDFs
  • For forensic examination of weaponized document artifacts
  • When building detection signatures for PDF-based threats

Prerequisites

  • Python 3.8+ with peepdf-3 installed (pip install peepdf-3)
  • pdfid.py and pdf-parser.py from Didier Stevens suite
  • Isolated analysis environment (VM or sandbox)
  • Optional: PyV8 for JavaScript emulation within peepdf
  • Optional: Pylibemu for shellcode analysis

Workflow

  1. Triage with pdfid: Scan PDF for suspicious keywords (/JS, /JavaScript, /OpenAction, /Launch, /EmbeddedFile).
  2. Interactive Analysis: Open PDF in peepdf interactive mode to explore object structure.
  3. Identify Suspicious Objects: Locate objects containing JavaScript, streams, or encoded data.
  4. Extract Content: Dump suspicious streams and decode filters (FlateDecode, ASCIIHexDecode).
  5. Deobfuscate JavaScript: Analyze extracted JS for shellcode, heap sprays, or exploit code.
  6. Check VirusTotal: Use peepdf vtcheck to cross-reference file hash with AV detections.
  7. Generate IOCs: Extract URLs, domains, hashes, and shellcode signatures.

Key Concepts

Concept Description
/OpenAction Automatic action executed when PDF is opened
/JavaScript /JS Embedded JavaScript code in PDF objects
/Launch Action that launches external applications
/EmbeddedFile File embedded within the PDF structure
FlateDecode zlib compression filter used to hide content
Object Streams PDF objects stored in compressed streams

Tools & Systems

Tool Purpose
peepdf / peepdf-3 Interactive PDF analysis with JS emulation
pdfid.py Quick triage scanning for suspicious keywords
pdf-parser.py Deep object-level PDF parsing
VirusTotal Hash lookup and AV detection cross-reference
CyberChef Decode and transform extracted payloads

Read the full file on GitHub · 97 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 97 lines · 73 tokens per session scan A 7cdd9a208444

Subscribe to this mod's changes

analyzing-malicious-pdf-with-peepdf is a skill published in the GitHub repository Youngmaidainon/Agent-Level-Up (3 stars, last pushed 16d ago), licensed MIT. It adds 73 tokens to every session and 803 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to analyzing-malicious-pdf-with-peepdf, differing in 0 lines, and is treated as a copy.

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