re-packer-id

Identify packers and obfuscators on PE binaries using signatures, section names, entry point, and entropy.

64|9|Updated Aug 17, 2026
One-click install
npx skills add https://github.com/dslsdzc/rev-skills --skill re-packer-id-dslsdzc
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: re-packer-id
Source: https://github.com/dslsdzc/rev-skills/tree/main/.claude/skills/re-packer-id
Command: npx skills add https://github.com/dslsdzc/rev-skills --skill re-packer-id-dslsdzc

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires pefile.

What problem does it solve? When analyzing an unknown binary, you must first determine whether it is packed and which packer was used before choosing an unpacking strategy. This Skill provides a structured identification workflow combining signature scanning, section-name inspection, entry-point analysis, entropy measurement, and import-table checks so you avoid misjudging packed samples as clean or vice versa. ## Core Features & Use Cases - Signature-based detection: Scan samples with Detect It Easy (diec) and PEiD to identify known packers such as UPX, ASPack, FSG, VMProtect, and Themida. - Multi-feature cross-validation: Combine section names, entry-point location, entropy above 7.0 bits/byte, and minimal import tables to detect unknown or signature-missing packers. - OEP clue recording: Capture entry-point instructions (e.g., pushad) and addresses during identification for later use with the ESP law during unpacking. - Use Case: You receive a suspicious PE sample with almost no readable strings. Run the workflow to confirm it is packed, identify it as UPX 3.x, record the entry instructions, and route it to the simple unpacking path. ## Quick Start Analyze the attached sample.exe to determine whether it is packed, identify the packer name and version, and record entry-point clues for unpacking.

Frequently Asked Questions about re-packer-id

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I check if a PE file is packed?▼

Scan the file with Detect It Easy (diec) or PEiD for signature matches, then cross-check section names, entry-point location, entropy above 7.0 bits/byte, and import table size. A tiny import table plus high entropy strongly indicates packing.

What tools detect packers like UPX or Themida?▼

Detect It Easy is the cross-platform primary tool with CLI (diec) and GUI modes, while PEiD serves as a Windows-based secondary checker with updated signature databases. Use both together when one fails to identify the packer.

Why does Detect It Easy report no packer on a suspicious file?▼

Signature databases may not cover private or niche packers, so a negative result does not mean the file is clean. Combine section-name, entry-point, entropy, and import-table features to judge, and treat it as an unknown packer if anomalies persist.

Can entropy analysis alone confirm a binary is packed?▼

No. Entropy above 7.0 bits/byte is a strong indicator but must be combined with other features, since packed section names can be disguised as .text or .data. Per-section entropy distribution is more meaningful than whole-file entropy.

How do I handle multi-layer packed samples?▼

Unpack one layer, then re-run identification on the result, checking PE header, section names, entropy distribution, and import table after each layer. Only when all four features look normal is the sample fully unpacked.

Does identifying the packer name mean all protections are enabled?▼

No. A packer name like VMProtect only indicates which packer was used; virtualization and anti-debugging are build-time options. Check for sections like .vmp0 or .themida and the entry stub type to determine the actual protection level.