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 analyzing-excel-4-macro-malwaregit 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/analyzing-excel-4-macro-malware)<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/analyzing-excel-4-macro-malware"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/analyzing-excel-4-macro-malware/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/analyzing-excel-4-macro-malware"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/analyzing-excel-4-macro-malware.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 | $0.00091 | $0.00778 |
| Opus 5 | $0.00046 | $0.00389 |
| Sonnet 5 | $0.00018 | $0.00156 |
| Haiku 4.5 | $0.00009 | $0.00078 |
Grade A, and why
analyzing-excel-4-macro-malware 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 — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Analyzing Excel 4.0 Macro Malware
When to Use
- You have an extracted Excel 4.0 (XLM) macro sheet (e.g., from a
.xls/.xlsmdumped with oletools/XLMMacroDeobfuscator) and need to find auto-run cells and execution primitives. - You are triaging maldocs that hide logic in legacy macro sheets rather than VBA.
Do not use Excel to open the document to "see" the macro — opening triggers the auto-run cells. Work from the extracted formula text statically.
Prerequisites
- The extracted XLM formula text (cell address → formula). Optional:
oletoolsto extract it.
Safety & Handling
- Never open the workbook in Excel; analyze the extracted formulas inertly. Defang URLs.
Workflow
Step 1: Find auto-executing entry points
python scripts/analyst.py analyze macros.txt
Flags defined-name triggers (Auto_Open, Auto_Close) and the cells they point to, plus
=HALT()/=RETURN() flow markers.
Step 2: Identify execution and download primitives
Detects EXEC(, CALL(, REGISTER( (Win32 imports), and URLDownload-style CALL patterns that
fetch and run a payload.
Step 3: Unwind obfuscation
Surfaces CHAR()/& string-building, FORMULA.FILL/FORMULA self-writing, and base/MID
slicing used to hide strings; reconstructs concatenated literals where possible.
Step 4: Extract IOCs
Pull URLs/paths and defang them; record the execution method (regsvr32, rundll32, mshta).
Validation
- Auto-run entry cells are identified, not just the presence of macros.
- Execution primitives (EXEC/CALL/REGISTER) are reported with their arguments.
- Reconstructed strings and URLs are defanged.
Pitfalls
- Heavily obfuscated sheets that self-write cells at runtime — static reconstruction is partial.
- Macro sheets hidden as
Very Hiddenthat simple viewers miss. - Confusing benign legacy spreadsheets that legitimately use XLM.
References
- See
references/api-reference.mdfor the analyzer. - ATT&CK T1059.005 and the Excel 4.0 macro reference (linked in frontmatter).
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 · 90 lines · 91 tokens per session scan A adb1d9804a4f
analyzing-excel-4-macro-malware is a skill published in the GitHub repository meltedinhex/analyst-ai-pack (22 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 91 tokens to every session and 778 once invoked, about $0.0005 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 2026-08-30.
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