Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/hermeticormus/linux-sysadmin-skills/sysadmin-securitynpx skills add HermeticOrmus/linux-sysadmin-skills --skill sysadmin-securitygit clone --depth 1 https://github.com/HermeticOrmus/linux-sysadmin-skillsWhat 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 | $0.00057 | $0.00614 |
| Opus 5 | $0.00028 | $0.00307 |
| Sonnet 5 | $0.00011 | $0.00123 |
| Haiku 4.5 | $0.00006 | $0.00061 |
Grade B, and why
sysadmin-security 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 2d 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 rootlowPrivilege escalation
A mod that escalates privileges can change anything on the machine, not only the project.
- Verify sudo permissions. Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
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.
- Review `~/.ssh/authorized_keys`. Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
How it starts
The opening of the file, as written. The whole thing — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.
System security audit
Audit and improve the security of a Debian/Ubuntu Linux machine. Work through the checklist below interactively. Inspection is read-only and runs freely; every change is explained first, including how it could lock you out, and waits for confirmation.
Security checklist
1. User and access control
- Review user accounts: who should have access?
- Check for unused accounts.
- Verify sudo permissions.
- Review SSH keys.
- Check password policies.
- Disable root login over SSH.
2. SSH hardening
- Disable password authentication in favor of keys.
- Change the default SSH port (optional).
- Configure fail2ban.
- Limit SSH access by user or IP.
- Use SSH key passphrases.
- Review
~/.ssh/authorized_keys.
3. Firewall
- Enable UFW (Uncomplicated Firewall).
- Configure allowed ports.
- Block unnecessary services.
- Review current rules.
- Set a default-deny policy.
4. Updates and patches
- Check for system updates with
apt update. - Enable automatic security updates.
- Review update history.
- Check for end-of-life software.
5. Services and ports
- List running services with
systemctl. - Disable unnecessary services.
- Review open ports with
ss -tlnp. - Check listening services.
- Verify service permissions.
6. File permissions
- Check sensitive file permissions (
/etc/passwd,/etc/shadow). - Review home directory permissions.
- Check SUID/SGID files.
- Verify critical system files.
7. Logs and monitoring
- Review system logs with
journalctl. - Check authentication logs.
- Monitor failed login attempts.
- Set up log rotation.
- Consider log monitoring tools.
8. Application security
- Review installed packages with
apt list --installed. - Remove unnecessary software.
- Check for vulnerable packages.
- Update applications.
- Verify sources (PPAs, repositories).
9. Network security
- Review network interfaces.
- Check the routing table.
- Verify DNS settings.
- Review
/etc/hosts. - Check for suspicious connections.
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.
- 2d ago First seen · 101 lines · 57 tokens per session scan B 192c77ec0980
sysadmin-security is a skill published in the GitHub repository HermeticOrmus/linux-sysadmin-skills (2 stars, last pushed 3mo ago), licensed MIT. It adds 57 tokens to every session and 614 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 2 findings (asks for root, reaches for credential files). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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