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-file-uploadWrote 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-file-upload)<a href="https://agentmods.dev/skills/snailsploit/claude-red/offensive-file-upload"><img src="https://agentmods.dev/badge/skills/snailsploit/claude-red/offensive-file-upload/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-file-upload"><img src="https://agentmods.dev/badge/skills/snailsploit/claude-red/offensive-file-upload.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 8 findings, up to critical
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 →
- critical YARA Match · line 177 YARA rule matched a known webshell pattern (PHP, Python, JSP, or ASPX webshell).Fix: Remove the webshell code immediately. Webshells provide unauthorized remote command execution. Audit the skill for additional backdoors or persistence mechanisms.
- critical YARA Match · line 450 YARA rule matched a known malware signature (reverse shell, backdoor, ransomware, C2 framework, or info stealer).Fix: Remove the malware payload or compromised file entirely. Investigate how it entered the skill and audit all other artifacts for additional indicators of compromise.
- critical YARA Match · line 623 YARA rule matched a known webshell pattern (PHP, Python, JSP, or ASPX webshell).Fix: Remove the webshell code immediately. Webshells provide unauthorized remote command execution. Audit the skill for additional backdoors or persistence mechanisms.
- high Privilege Escalation · line 193 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 194 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 208 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 312 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 Privilege Escalation · line 209 Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
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 | $0.00000 | $0.07736 |
| Opus 5.5 | $0.00000 | $0.03094 |
| Sonnet 5.5 | $0.00000 | $0.01547 |
| Haiku 4.5 | $0.00000 | $0.00774 |
Grade B, and why
offensive-file-upload scanned grade B 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 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.
Asks for rootmediumPrivilege escalation
A mod that escalates privileges can change anything on the machine, not only the project.
- **Tar Permissions Abuse**: Create tar with restrictive parent dir permissions (`chmod 300`) but permissive subdir (`chmod 700`) containing symlinks. Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
response = requests.post(target_url, data=multipart_data, headers=headers) Copies of this mod
1 near-identical copy found in the catalogue:
- offensive-file-upload — 91% identical, 53 lines differ
How it starts
The opening of the file, as written. The whole thing — 821 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SKILL: File Upload Vulnerabilities
Metadata
- Skill Name: file-upload
- Folder: offensive-file-upload
- Source: https://github.com/SnailSploit/offensive-checklist/blob/main/file-upload.md
Description
File upload vulnerability checklist: MIME type bypass, extension bypass, magic byte manipulation, path traversal in filenames, stored XSS via SVG/HTML upload, server-side processing attacks, and race conditions. Use for assessing file upload endpoints in web app pentests or bug bounty.
Trigger Phrases
Use this skill when the conversation involves any of:
file upload, MIME bypass, extension bypass, magic byte, path traversal upload, SVG XSS, polyglot, upload bypass, malicious upload, web shell upload
Instructions for Claude
When this skill is active:
- Load and apply the full methodology below as your operational checklist
- Follow steps in order unless the user specifies otherwise
- For each technique, consider applicability to the current target/context
- Track which checklist items have been completed
- Suggest next steps based on findings
Full Methodology
File Upload Vulnerabilities
Mechanisms
flowchart TD
A[File Upload Vulnerabilities] --> B[Insufficient File Type Validation]
A --> C[Improper Extension Handling]
A --> D[Inadequate File Content Analysis]
A --> E[Unsafe File Storage]
A --> F[File Operation Mishandling]
A --> G[Directory Traversal]
A --> H[Race Conditions]
B --> I[Remote Code Execution]
C --> I
D --> J[Client-Side Attacks]
E --> I
F --> K[Denial of Service]
G --> L[Arbitrary File Access]
H --> I
File upload vulnerabilities occur when web applications allow users to upload files without implementing proper validation, filtering, and handling mechanisms. These vulnerabilities can lead to various attacks, ranging from simple web defacement to complete server compromise through remote code execution.
The core technical issues behind file upload vulnerabilities include:
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 · 821 lines · 0 tokens per session scan B afd9029b2171
offensive-file-upload is a skill published in the GitHub repository SnailSploit/Claude-Red (7,620 stars, last pushed 8d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 7,736 tokens. A static security scan graded it B with 2 findings (asks for root, 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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