A read-only scanner that applies YARA rules to files or directories. YARA is a tool for matching patterns associated with malware or other files of interest; the scanner does not run the target.

Use it to scan targets with the included starter rules or your own rule collection, using the classic YARA command-line tool or yara-x, and report matching rules and targets.

It adds signature-based checks to file triage, helping find known patterns in packages, extracted archives, samples, or directory trees.

yara-scan — Skill for Claude Code and Codex by batteryshark

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 batteryshark/rekit --skill yara-scan

Clone the repo

git clone --depth 1 https://github.com/batteryshark/rekit

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/batteryshark/rekit/yara-scan.svg)](https://agentmods.dev/skills/batteryshark/rekit/yara-scan)

Your own site

<a href="https://agentmods.dev/skills/batteryshark/rekit/yara-scan"><img src="https://agentmods.dev/badge/skills/batteryshark/rekit/yara-scan.svg" alt="Measured on agentmods" height="20"></a>

Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 481 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found 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.

Model	Per session	Once invoked
Fable 5.1	$0.00080	$0.00481
Opus 5	$0.00040	$0.00241
Sonnet 5	$0.00016	$0.00096
Haiku 4.5	$0.00008	$0.00048

Measured 6d ago against content hash b17cdd5cccdb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

yara-scan scanned grade A with 1 finding 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 6d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/run.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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

PE, UPX packing, PHP webshell eval, Windows exec/download cradles, and `curl|sh`

skills/yara-scan/SKILL.md · 41 lines

What it actually says

YARA Scanner

Scan a file or directory with YARA rules — the standard way to match known malware patterns/families.

When to use

Any triage where you want signature coverage: run it over a package, an extracted archive, a dropped sample, or a whole tree. Complements the behavioural covert-scan skills (which look at tactics) with signature matching.

What it does

Runs yara (or yara-x/yr) with your rules over the target and reports each match as {rule, target}. Read-only — YARA matches patterns; it never runs the target.

Ships a small starter rule pack (assets/starter.yar): embedded/base64-encoded PE, UPX packing, PHP webshell eval, Windows exec/download cradles, and curl|sh droppers. This is a starting point, not a corpus — for real coverage point --rules at YARA-Rules, Neo23x0/signature-base, or your own set.

Usage

rekit run yara-scan ./package                       # starter rules over a tree
rekit run yara-scan ./sample.bin --rules ~/rules    # your own corpus
rekit run yara-scan ./x --format json

Prerequisites

python3 (runner) and the yara CLI (or yara-x) on PATH — a native tool, not bundled. Until it's installed, doctor marks the skill not-ready and run reports the honest gap with an install hint. (The starter rules ship with the skill.)

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.

6d ago First seen · 41 lines · 80 tokens per session scan A b17cdd5cccdb

Subscribe to this mod's changes

yara-scan is a skill published in the GitHub repository batteryshark/rekit (10 stars, last pushed 28d ago), licensed Apache-2.0. It adds 80 tokens to every session and 481 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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