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.
npx skills add meltedinhex/analyst-ai-pack --skill unpacking-upx-and-common-packersgit clone --depth 1 https://github.com/meltedinhex/analyst-ai-packWrote 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.
[](https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/unpacking-upx-and-common-packers)<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/unpacking-upx-and-common-packers"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/unpacking-upx-and-common-packers/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.
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/unpacking-upx-and-common-packers"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/unpacking-upx-and-common-packers.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00076 | $0.00851 |
| Opus 5 | $0.00038 | $0.00426 |
| Sonnet 5 | $0.00015 | $0.00170 |
| Haiku 4.5 | $0.00008 | $0.00085 |
Grade A, and why
unpacking-upx-and-common-packers 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 9d ago.
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.
How it starts
The opening of the file, as written. The whole thing — 102 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Unpacking UPX and Common Packers
When to Use
- A sample shows high entropy, few imports, or packer section names, and you need the original code for static analysis or RE.
- You want to unpack UPX automatically or manually unpack a custom/modified packer.
- You are preparing a sample for Ghidra/IDA (decompiling packed code is pointless).
Do not use generic unpackers as a guarantee — modified UPX and custom packers defeat
upx -d. Fall back to debugger-based manual unpacking.
Prerequisites
- Packer detection (Detect It Easy, or the bundled section/entropy heuristics).
upxfor standard UPX; x64dbg + Scylla for manual unpacking (see the x64dbg skill).- Isolated lab.
Workflow
Step 1: Detect the packer
python scripts/analyst.py detect sample.bin
Signals: section names (UPX0/UPX1, .aspack, .themida), high section entropy, a tiny
import table, and a small .text with a large high-entropy section.
Step 2: Try automated UPX unpacking
If standard UPX:
upx -d -o sample_unpacked.bin sample.bin
If upx -d fails on a UPX-like sample, the header was likely tampered (e.g. UPX! magic or
version bytes altered) — repair the marker or unpack manually.
Step 3: Manual unpacking for custom packers
In x64dbg: break on VirtualAlloc/VirtualProtect, run until the unpacked region is written
and made executable, find the tail jump to the original entry point (OEP), and dump there.
Step 4: Dump and rebuild imports
Use Scylla to dump the process and reconstruct the Import Address Table (IAT) so the dumped PE loads in a disassembler.
Step 5: Verify the unpacked result
Confirm the dump is a clean PE with a populated import table and readable strings/code.
Validation
- The unpacked file has restored imports and meaningful strings absent from the packed sample.
- Entropy of the unpacked
.textdrops to normal code levels. - The disassembler resolves API calls (IAT rebuilt correctly).
Pitfalls
What ships with it
3 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.
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.
- 9d ago First seen · 102 lines · 76 tokens per session scan A 2a4e65379e83
unpacking-upx-and-common-packers is a skill published in the GitHub repository meltedinhex/analyst-ai-pack (22 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 76 tokens to every session and 851 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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