An incident-response command for examining possible signs of an attack against an Nginx setup.

Use it to parse YARA, text, or STIX indicators, look up a CVE, poll configured feeds, cross-reference Nginx logs, and generate candidate or emergency containment rules.

It brings together indicators, known vulnerability information, threat feeds, and logs so suspicious activity can be reviewed and contained.

ioc-nginx — Command for Claude Code by trumb

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.

Clone the repo

git clone --depth 1 https://github.com/trumb/claude-nginx-hardening

Made for: Claude Code.

Or install claude-nginx-hardening, the plugin that ships this one along with the rest of its 1 skill, 8 commands, 3 agents.

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/commands/trumb/claude-nginx-hardening/ioc-nginx/github.svg)](https://agentmods.dev/commands/trumb/claude-nginx-hardening/ioc-nginx)

Your own site

<a href="https://agentmods.dev/commands/trumb/claude-nginx-hardening/ioc-nginx"><img src="https://agentmods.dev/badge/commands/trumb/claude-nginx-hardening/ioc-nginx/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.

Your own site · 80×15

<a href="https://agentmods.dev/commands/trumb/claude-nginx-hardening/ioc-nginx"><img src="https://agentmods.dev/badge/commands/trumb/claude-nginx-hardening/ioc-nginx.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 28 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 1,162 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. 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	$0.00028	$0.01162
Opus 5	$0.00014	$0.00581
Sonnet 5	$0.00006	$0.00232
Haiku 4.5	$0.00003	$0.00116

Measured 12d ago against content hash 9342d3f96342, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

ioc-nginx 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 12d 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.

commands/ioc-nginx.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Context

Threat feeds configured: !python3 scripts/feed-poller.py --list 2>/dev/null | python3 -c "import sys,json; d=json.load(sys.stdin); print(f'{len([f for f in d[\"feeds\"] if f[\"status\"]==\"available\"])} available')" 2>/dev/null || echo "feed-poller not available"
Recent findings: !ls outputs/run-*/findings.json 2>/dev/null | wc -l run(s) with findings
Log data: !ls /var/log/nginx/*.log 2>/dev/null | wc -l log files

Operating Mode

DEFAULT: R0 + R1 (Advisory — cross-reference only) With --stage: R1 (generate candidate rules) With --emergency: W1 (emergency containment — Class A only, narrow scope)

Read @skills/nginx-hardening/EXECUTION-POLICY.md and @skills/nginx-hardening/RULE-CLASSES.md.

Invocation

Parse local IoC source

/harden-nginx ioc /path/to/rule.yar — Parse YARA rule file
/harden-nginx ioc /path/to/indicators.txt — Parse text indicator list
/harden-nginx ioc /path/to/stix.json — Parse STIX JSON

CVE lookup

/harden-nginx ioc CVE-2021-44228 — Look up CVE, generate rules for known exploit paths

Interactive

/harden-nginx ioc — Describe the IoC, paste indicators, or select a source

Feed polling

/harden-nginx ioc --feed — Poll all configured threat feeds
/harden-nginx ioc --feed cisa_kev,urlhaus — Poll specific feeds

Response Modes

Advisory (default)

Cross-reference indicators against existing logs and rules. Report: "Indicator X has been seen N times", "Indicator Y is already blocked by rule Z", "Indicator Z is NOT blocked". No rule generation.

Stage (--stage)

Everything in Advisory, plus:

Generate candidate blocking rules for unblocked indicators
Assign rule class (prefer Class A — Containment)
Assign severity from source confidence and CVSS score
Write proposals to outputs//ioc-proposed-rules/
Create learning file in learnings/ioc-responses/

Emergency Containment (--emergency)

Everything in Stage, plus:

Apply Class A rules IMMEDIATELY (W1 execution)
ONLY allowed when ALL of:
- Rule class is A (Containment only)
- Scope is narrow (exact-location or server-block)
- Confidence >= 0.8
- TTL is assigned (default: 7 days, not permanent)
- All invariants pass
- Source provenance recorded

Read the full file on GitHub · 118 lines

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.

12d ago First seen · 118 lines · 28 tokens per session scan A 9342d3f96342

Subscribe to this mod's changes

ioc-nginx is a command published in the GitHub repository trumb/claude-nginx-hardening (3 stars, last pushed 5mo ago), licensed MIT. It adds 28 tokens to every session and 1,162 once invoked, about $0.0001 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 2026-08-31.

Security

ioc-nginx