Recon Skills is a pack of security-testing skills covering reconnaissance, web applications, APIs, authentication, vulnerability validation, cloud infrastructure, and reporting. Security professionals use it for authorized assessments of systems they own or have written permission to test. The catalogue entries are individual skills from the pack.
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 uphiago/recon-skills --skill s3-minio-content-type-xssgit clone --depth 1 https://github.com/uphiago/recon-skillsWrote 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/uphiago/recon-skills/s3-minio-content-type-xss)<a href="https://agentmods.dev/skills/uphiago/recon-skills/s3-minio-content-type-xss"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/s3-minio-content-type-xss/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/uphiago/recon-skills/s3-minio-content-type-xss"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/s3-minio-content-type-xss.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00024 | $0.01814 |
| Opus 5 | $0.00012 | $0.00907 |
| Sonnet 5 | $0.00005 | $0.00363 |
| Haiku 4.5 | $0.00002 | $0.00181 |
Grade A, and why
s3-minio-content-type-xss 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 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
compatibility: Requires curl, python3 How it starts
The opening of the file, as written. The whole thing — 169 lines — stays where its author put it; the contents beside it link to each section on GitHub.
S3/MinIO Content-Type Override to Stored XSS
Exploit public cloud storage buckets (S3, MinIO, and compatible) by overriding the Content-Type response header via query parameters. When a target serves user-uploaded files from its own origin (e.g., cdn.target.com or target.com/uploads/), a successful override turns a stored HTML/JS payload into same-origin stored XSS — bypassing every upload-time validation the application performed.
When to Use
- Target serves user-uploaded files (images, avatars, attachments) from a public bucket.
- Files are served under the target's own domain or subdomain (not a random storage domain).
- Upload validation appears solid (extension whitelist, magic byte check, forced Content-Type) — the override bypasses all of these at serve time, not upload time.
- The bucket URL responds to
?response-content-type=with a changed Content-Type. - The bucket returns an AWS SignatureDoesNotMatch error leaking the real bucket host and region.
Prerequisites
terminalwith curl and python3.- Identify at least one public object URL served from storage.
- For S3 exploitation: your own AWS account credentials (free tier sufficient).
Quick Detection
# Test if an object's Content-Type can be overridden (MinIO and compatible)
curl --max-time 30 --connect-timeout 10 -skI "https://cdn.target.com/uploads/avatar123.png?response-content-type=text/html" | grep -i content-type
# If you get 'text/html', the override works — proceed to exploitation
# If you get 'Request specific response headers cannot be used for anonymous GET requests', it's S3 — use signed URL approach
Procedure
Phase 1 — Identify Public Objects
Find uploaded objects served publicly:
# Check common upload paths
for path in /uploads/ /media/ /static/uploads/ /cdn/ /files/ /assets/img/ /storage/; do
curl --max-time 30 --connect-timeout 10 -skI "https://target.com${path}" | grep -E "HTTP|Content-Type|x-amz"
done
# Look for S3/MinIO signatures in URLs
curl --max-time 30 --connect-timeout 10 -sk "https://target.com/" | grep -Eo '(?:s3\.|amazonaws\.|minio|storage\.googleapis)[^"'\''\s]{5,60}'
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 · 169 lines · 24 tokens per session scan A 87aea3c1a56b
s3-minio-content-type-xss is a skill published in the GitHub repository uphiago/recon-skills (1,254 stars, last pushed 10d ago), licensed MIT. It adds 24 tokens to every session and 1,814 once invoked, about $0.0001 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.
Other skills, from other repositories
auditing-aws-s3-bucket-permissions
Systematically audit AWS S3 bucket permissions to identify publicly accessible buckets, overly permissive ACLs, misconfigured bucket policies, and missing encryption settings using AWS CLI, S3audit, and Prowler to enforce least-privilege data access controls.
detecting-s3-data-exfiltration-attempts
Detecting data exfiltration attempts from AWS S3 buckets by analyzing CloudTrail S3 data events, VPC Flow Logs, GuardDuty findings, Amazon Macie alerts, and S3 access patterns to identify unauthorized bulk downloads and cross-account data transfers.
performing-cloud-forensics-with-aws-cloudtrail
Perform forensic investigation of AWS environments using CloudTrail logs to reconstruct attacker activity, identify compromised credentials, and analyze API call patterns.
minio
Operate Joel's MinIO legacy/rollback services and S3-compatible object storage checks. Use for MinIO, ASUSTOR MinIO CE, custom Docker/Compose MinIO, Convex MinIO rollback, and MinIO-vs-Garage questions. For canonical local Convex object storage, use Garage/local-convex.
auditing-aws-s3-bucket-permissions
Systematically audit AWS S3 bucket permissions to identify publicly accessible buckets, overly permissive ACLs, misconfigured bucket policies, and missing encryption settings using AWS CLI, S3audit, and Prowler to enforce least-privilege data access controls.
files-sdk
Use files-sdk to add file storage to a TypeScript/JavaScript app with a unified API across S3, R2, GCS, Azure, Vercel Blob, the local filesystem, and 40+ other providers. Triggers when the user wants to upload/download/list/move/delete/copy files, generate presigned URLs, do multipart or resumable uploads, range…