security-investigator: Skill for Claude Code

.github/skills/app-registration-posture/SKILL.md

app-registration-posture is a skill for Claude Code, Codex from SCStelz/security-investigator. It costs 176 tokens per session (20,402 once invoked), scanned A, original, MIT.

A security audit tool for Microsoft Entra app registrations and service principals, which are applications and identities that can access an organization’s services. It reviews permissions, owners, credentials, and cross-tenant risks.

In plain words
What is it for?
Use it to find dangerous permissions, risky or missing owners, stale or long-lived secrets, unusual credentials, and suspicious service-principal access patterns.
Why use it?
It helps find over-privileged or poorly maintained applications that attackers could abuse for access or persistence.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

This is SCStelz/security-investigator's own configuration. It tells Claude Code and Codex how to work on security-investigator itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything security-investigator configures →

Reuse

Borrowing it

Nothing to install: this file belongs to SCStelz/security-investigator. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/SCStelz/security-investigator/main/.github/skills/app-registration-posture/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/SCStelz/security-investigator

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.

agentmods badge for app-registration-posture

README.md
[![agentmods](https://agentmods.dev/badge/skills/scstelz/security-investigator/app-registration-posture/github.svg)](https://agentmods.dev/skills/scstelz/security-investigator/app-registration-posture)
Your own site
<a href="https://agentmods.dev/skills/scstelz/security-investigator/app-registration-posture"><img src="https://agentmods.dev/badge/skills/scstelz/security-investigator/app-registration-posture/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.

agentmods 80×15 button for app-registration-posture

Your own site · 80×15
<a href="https://agentmods.dev/skills/scstelz/security-investigator/app-registration-posture"><img src="https://agentmods.dev/badge/skills/scstelz/security-investigator/app-registration-posture.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 176 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 20,402 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 6 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Privilege Escalation · line 51
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 97
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • medium Agent Snooping · line 1523
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • low Privilege Escalation · line 1398
    Skill requests more permissions than appear necessary for its stated functionality. Review if elevated access is justified.
    Fix: Request only the minimum permissions required. Document why each permission is needed. Remove broad permissions like '*' or 'all'.
  • low Privilege Escalation · line 1399
    Skill requests more permissions than appear necessary for its stated functionality. Review if elevated access is justified.
    Fix: Request only the minimum permissions required. Document why each permission is needed. Remove broad permissions like '*' or 'all'.
  • low Privilege Escalation · line 1477
    Skill requests more permissions than appear necessary for its stated functionality. Review if elevated access is justified.
    Fix: Request only the minimum permissions required. Document why each permission is needed. Remove broad permissions like '*' or 'all'.
How audits are shown
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00176 $0.20402
Opus 5 $0.00088 $0.10201
Sonnet 5 $0.00035 $0.04080
Haiku 4.5 $0.00018 $0.02040

Measured 11d ago against content hash 82fd64ebe3d0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

app-registration-posture 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 11d 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.

.github/skills/app-registration-posture/SKILL.md · 1,527 lines

How it starts

The opening of the file, as written. The whole thing — 1,527 lines — stays where its author put it; the contents beside it link to each section on GitHub.

App Registration Security Posture — Instructions

Purpose

This skill audits the security posture of Entra ID App Registrations and Service Principals across your organization, combining Graph API current-state inventory with KQL attack chain detection to create a comprehensive assessment.

App Registrations are a growing persistence and lateral movement vector. Attackers who compromise a user with app ownership can add credentials (secrets/certificates), disconnect from the user session, and authenticate as the service principal — inheriting all the app's permissions. This is the exact pattern documented in the Guardz research and used in the SolarWinds/Solorigate attack.

What this skill covers:

Domain Key Questions Answered Data Source
🔐 Permission Inventory Which apps have dangerous Graph API permissions? How concentrated are critical permissions? Graph API
👤 Owner Risk Which app owners are non-admin users (phishing targets)? Are owners currently risky? Ownerless apps? Graph API + Q1
🔑 Credential Hygiene Stale secrets, multi-credential apps, long-lived credentials, cert+secret anomalies Graph API
🌐 Cross-Tenant Exposure Foreign SPNs authenticating into your tenant with dangerous permissions Q4
Active Abuse Chains Risky user → app ops, credential add → SPN activation, ownership → credential chains, Graph API lateral movement, permission escalation, multi-app ownership spread, App Governance & OAuth incident cross-reference Q1–Q8

How this differs from existing capabilities:

Existing Resource Coverage Gap This Skill Fills
app_credential_management.md Individual credential/ownership/consent events No cross-table chain correlation
service_principal_scope_drift.md SPN behavioral baseline drift No link to preceding compromise signals
App Governance (Microsoft) Anomalous app behavior, overprivileged apps No correlation with user risk signals or multi-step chains
This skill Graph API posture + KQL chain detection End-to-end: current state → historical abuse → risk scoring

Read the full file on GitHub · 1,527 lines

Files

What ships with it

1 file 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.

  1. 11d ago First seen · 1,527 lines · 176 tokens per session scan A 82fd64ebe3d0

Subscribe to this mod's changes

app-registration-posture is a skill published in the GitHub repository SCStelz/security-investigator (245 stars, last pushed 3d ago), licensed MIT. It adds 176 tokens to every session and 20,402 once invoked, about $0.0009 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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