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 deobfuscating-malicious-powershellgit 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/deobfuscating-malicious-powershell)<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/deobfuscating-malicious-powershell"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/deobfuscating-malicious-powershell.svg" alt="Measured on agentmods" 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 | $0.00071 | $0.00932 |
| Opus 5 | $0.00036 | $0.00466 |
| Sonnet 5 | $0.00014 | $0.00186 |
| Haiku 4.5 | $0.00007 | $0.00093 |
Grade A, and why
deobfuscating-malicious-powershell 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 7d 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 — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Deobfuscating Malicious PowerShell
When to Use
- You captured an obfuscated PowerShell command from a log, maldoc, or phishing payload.
- You need to recover the real intent: download URLs, dropped paths, shellcode, or next stage.
- You are unrolling layered encoding (base64 → gzip → IEX) to reach the final script.
Do not use Invoke-Expression or run the script to "see what it does" on a working host.
Decode statically; only execute in the isolated lab with logging if dynamic confirmation is
required.
Prerequisites
- Python (bundled script handles base64/gzip/deflate and common transforms), or a sandbox.
- The command/script text captured as a string.
Safety & Handling
- Never pipe attacker PowerShell into a live shell. Replace
IEX/Invoke-Expressionwith output (print) when transforming. - Treat decoded URLs/IPs as live; defang before sharing.
Workflow
Step 1: Decode -EncodedCommand
-EncodedCommand (-enc) is base64 of UTF-16LE. Decode it first:
python scripts/analyst.py decode --encodedcommand "<base64>"
Step 2: Identify the obfuscation style
Common patterns:
String reversal : [array]::Reverse / -join with [-1..]
Format operator : ("{1}{0}" -f 'b','a') -> 'ab'
Char codes : [char]104 + [char]105
Concatenation/splits : 'po'+'wer'+'shell', -split / -replace tricks
Backtick/casing noise : I`E`X, iEx, &('i'+'ex')
Step 3: Unroll encoding layers
Resolve nested FromBase64String, gzip/deflate (IO.Compression), and re-IEX layers until
you reach plain script. The script peels base64/gzip layers automatically.
python scripts/analyst.py deobfuscate payload.ps1
Step 4: Neutralize execution sinks
Replace IEX, Invoke-Expression, &, and .Invoke() with a print so the recovered script
is rendered, not run.
Step 5: Extract IOCs
Pull DownloadString/DownloadFile URLs, C2 hosts, dropped paths, and any embedded
base64 shellcode for separate analysis.
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.
- 7d ago First seen · 112 lines · 71 tokens per session scan A 7aa22a56e157
deobfuscating-malicious-powershell is a skill published in the GitHub repository meltedinhex/analyst-ai-pack (22 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 71 tokens to every session and 932 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 2026-08-30.
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