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-grpcgit 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-grpc)<a href="https://agentmods.dev/skills/uphiago/recon-skills/hunt-grpc"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-grpc/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-grpc"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-grpc.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 9 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 YARA Match · line 30 YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).Fix: Remove offensive tool references and exploit code. Legitimate agent skills should not contain penetration testing tools, exploit frameworks, or reconnaissance utilities.
- medium Data Exfiltration · line 37 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 Data Exfiltration · line 41 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 Data Exfiltration · line 77 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 Data Exfiltration · line 106 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 Data Exfiltration · line 135 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 Data Exfiltration · line 171 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 Data Exfiltration · line 176 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 Data Exfiltration · line 283 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.
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 | $0.00135 | $0.05559 |
| Opus 5 | $0.00068 | $0.02780 |
| Sonnet 5 | $0.00027 | $0.01112 |
| Haiku 4.5 | $0.00014 | $0.00556 |
Grade A, and why
hunt-grpc scanned grade A with 2 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 8d 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.
Sends data to an external URLlowData exfiltration
A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.
grpcurl -plaintext $TARGET:50051 -d '{}' admin.AdminService/ListUsers Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl --max-time 30 --connect-timeout 10 -s --http2-prior-knowledge -X POST "http://$TARGET:9090/x.Y/Z" \ How it starts
The opening of the file, as written. The whole thing — 321 lines — stays where its author put it; the contents beside it link to each section on GitHub.
HUNT-GRPC — gRPC Security
Crown Jewel Targets
gRPC reflection enabled = full service catalog enumeration without source code. The highest-value gRPC bugs come from the architectural assumption that a service is "internal" — auth is enforced at the edge proxy, and the backend trusts any caller that reaches it. Once you reach the backend directly (exposed port, SSRF, proxy bypass), that trust collapses.
Highest-value findings:
- Reflection enabled in production —
grpc.reflection.v1alpha.ServerReflection/grpc.reflection.v1.ServerReflectionlists every method, message, and internal service. Enumeration enabler, not a vuln on its own (see Validation). - Missing auth on internal service — a service designed for east-west microservice traffic exposed externally with no mTLS and no per-method authorization → call privileged methods directly.
- Edge-auth-only / metadata-stripping — proxy authenticates the user but the backend re-trusts proxy-injected headers (
x-user-id,x-tenant-id,x-forwarded-*); if you reach the backend or can inject those headers via the proxy, you impersonate any tenant. - Plaintext gRPC — gRPC h2c (cleartext HTTP/2) on a non-standard port → credential/metadata interception.
- HTTP/2 Rapid Reset DoS (CVE-2023-44487) — interleaved HEADERS + immediate RST_STREAM frames bypass
MAX_CONCURRENT_STREAMSaccounting → resource exhaustion. DoS is in scope on almost no program — get explicit written authorization before sending a single burst.
Phase 1 — Fingerprint & Port Discovery
# Common gRPC ports (50051 native; 443/8443 via TLS+ALPN h2; 9090/8080 h2c)
nmap -sV -p 50051,50052,443,9090,8080,8443,6565,9000 $TARGET 2>/dev/null | grep open
# ALPN must negotiate h2 — gRPC cannot run on HTTP/1.1
echo | openssl s_client -alpn h2 -connect $TARGET:443 2>/dev/null | grep -i "ALPN.*h2"
# Native-gRPC fingerprint: an HTTP/2 POST to a bogus method returns a grpc-status
# trailer (12 = UNIMPLEMENTED) even when the path is wrong — strong signal it's gRPC.
curl --max-time 30 --connect-timeout 10 -s --http2-prior-knowledge -X POST "http://$TARGET:9090/x.Y/Z" \
-H "content-type: application/grpc" -o /dev/null -D - | grep -i grpc-status
# TLS-fronted h2 (port 443): look for grpc-status trailer / grpc content-type
curl --max-time 30 --connect-timeout 10 -s --http2 -X POST "https://$TARGET/grpc.health.v1.Health/Check" \
-H "content-type: application/grpc-web+proto" -o /dev/null -D - | grep -i "grpc-status\|content-type"
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.
- 8d ago First seen · 321 lines · 135 tokens per session scan A c7db6d101867
hunt-grpc is a skill published in the GitHub repository uphiago/recon-skills (1,254 stars, last pushed 10d ago), licensed MIT. It adds 135 tokens to every session and 5,559 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it A with 2 findings (sends data to an external url, 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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graphql-audit
GraphQL security hunting — introspection abuse, field suggestion enumeration (clairvoyance), batching DoS, IDOR via aliasing, auth bypass, injection via arguments, subscription abuse, depth/complexity bombs, and WAF bypass. Covers graphw00f fingerprinting, gqlmap, graphql-cop, and inql. Use when a target exposes a…
hunt-api-misconfig
Hunt API security misconfiguration — mass assignment, prototype pollution, HTTP verb tampering. Mass assignment: send {isadmin:true, role:admin, verified:true} on profile/account/reset endpoints — server blindly applies. JWT signature/crypto forging (alg:none, key confusion, kid/jku) is owned by hunt-jwt-crypto; this…
detecting-api-enumeration-attacks
Detect and prevent API enumeration attacks including BOLA and IDOR exploitation by monitoring sequential identifier access patterns and authorization failures.
detecting-broken-object-property-level-authorization
Detect and test for OWASP API3:2023 Broken Object Property Level Authorization vulnerabilities including excessive data exposure and mass assignment attacks.
detecting-shadow-api-endpoints
Discover and inventory shadow API endpoints that operate outside documented specifications using traffic analysis, code scanning, and API discovery platforms.