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 hunt-subdomaingit 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/hunt-subdomain)<a href="https://agentmods.dev/skills/uphiago/recon-skills/hunt-subdomain"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-subdomain/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/hunt-subdomain"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-subdomain.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 3 findings, up to medium
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 →
- medium Excessive Agency · line 275 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
- medium Data Exfiltration · line 298 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
- medium Excessive Agency · line 356 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
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 | $0.00131 | $0.06407 |
| Opus 5 | $0.00066 | $0.03204 |
| Sonnet 5 | $0.00026 | $0.01281 |
| Haiku 4.5 | $0.00013 | $0.00641 |
Grade A, and why
hunt-subdomain 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 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
- `curl --max-time 30 --connect-timeout 10 -sk https://subdomain.target.com` — check for provider error string How it starts
The opening of the file, as written. The whole thing — 371 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Crown Jewel Targets
Subdomain takeover is high-value because it allows an attacker to serve content from a trusted, company-owned domain — bypassing browser same-origin trust, phishing filters, and user skepticism simultaneously.
Highest payout contexts:
- Subdomains of major SaaS brands (Shopify, Snapchat, Mozilla, Yelp) where the trusted domain has user session context
- CDN-backed subdomains (Fastly, CloudFront) where CNAME points to unclaimed origins
- Third-party service integrations: UserVoice, WordPress.com, GitHub Pages, GitLab Pages, Heroku, Zendesk
- Preview/staging/dev subdomains (
new.,preview.,course.,delivery.,addons-preview.) — abandoned after feature launches - Subdomains used for OAuth redirect URIs or SSO endpoints — these pay highest
Asset types that matter most:
- CNAME records pointing to deprovisioned third-party services
- NS delegations to abandoned zones
- A records pointing to unallocated cloud IPs (less common)
- GitLab/GitHub Pages with unclaimed project namespaces
Attack Surface Signals
DNS signals:
CNAMEpointing to*.github.io,*.gitlab.io,*.fastly.net,*.herokudns.com,*.wordpress.com,*.uservoice.com,*.zendesk.com,*.s3.amazonaws.com,*.azurewebsites.net,*.netlify.app- NXDOMAIN or
SERVFAILon the CNAME target while the parent record still exists - NS records delegating to registrars where the zone is no longer registered
HTTP response signals:
"There isn't a GitHub Pages site here""NoSuchBucket"(S3)"The specified bucket does not exist""No such app"(Heroku)"Sorry, this shop is currently unavailable"(Shopify)"This UserVoice subdomain is available""Do you want to register"(any domain parking page)- HTTP 404 with provider-specific error templates
- Fastly:
"Fastly error: unknown domain" "404 Web Site not found"(Azure App Service)
Tech stack signals:
- Response headers:
X-Served-By: cache-*(Fastly),X-GitHub-Request-Id,Server: Netlify CNAMEchain resolving to provider infrastructure but returning provider 404- SSL cert issued to provider wildcard (
*.fastly.net) rather than company domain
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 · 371 lines · 131 tokens per session scan A b0e4c9b3a957
hunt-subdomain is a skill published in the GitHub repository uphiago/recon-skills (1,254 stars, last pushed 9d ago), licensed MIT. It adds 131 tokens to every session and 6,407 once invoked, about $0.0007 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 2026-09-03.
Other skills, from other repositories
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meme-coin-audit
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implementing-cloud-dlp-for-data-protection
Implementing Cloud Data Loss Prevention (DLP) using Amazon Macie, Azure Information Protection, and Google Cloud DLP API to discover, classify, and protect sensitive data across cloud storage, databases, and data pipelines.
auditing-gcp-iam-permissions
Auditing Google Cloud Platform IAM permissions to identify overly permissive bindings, primitive role usage, service account key proliferation, and cross-project access risks using gcloud CLI, Policy Analyzer, and IAM Recommender.
auditing-terraform-infrastructure-for-security
Auditing Terraform infrastructure-as-code for security misconfigurations using Checkov, tfsec, Terrascan, and OPA/Rego policies to detect overly permissive IAM policies, public resource exposure, missing encryption, and insecure defaults before cloud deployment.
detecting-compromised-cloud-credentials
Detecting compromised cloud credentials across AWS, Azure, and GCP by analyzing anomalous API activity, impossible travel patterns, unauthorized resource provisioning, and credential abuse indicators using GuardDuty, Defender for Identity, and SCC Event Threat Detection.