# Aeon Skill Security Scan

> Audit installed Bankr skills before you run them — scan SKILL.md and companion scripts for shell injection, secret exfiltration, path traversal, prompt-override payloads, destructive commands, and 2026-era obfuscation (zero-width Unicode, bidi override, base64-decode pipes, webhook SSRF hosts). Designed to integrate with Bankr Safety Scores. Silent on no-op runs; surfaces only NEW or RESOLVED findings vs prior scans. Triggers: "audit this skill", "is this skill safe to install", "security scan my skills", "check skill X for injection".

- Skill: `bankrbot/aeon-skill-security-scan-2` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add bankrbot/aeon-skill-security-scan-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/bankrbot/aeon-skill-security-scan-2/raw
- Safety review: pending (external: skill-scanner FAIL, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: BankrBot (https://skillmd.com/u/bankrbot)
- Updated: 2026-09-21
- Page: https://skillmd.com/skills/bankrbot/aeon-skill-security-scan-2

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# aeon-skill-security-scan

Skills tell agents what to do. A malicious or sloppy skill can shell-inject, exfiltrate secrets, override instructions, or run destructive commands. This skill scans every installed SKILL.md and companion script and surfaces the risks before they execute.

## Scope

- `<skills-dir>/*/SKILL.md` — primary.
- `<skills-dir>/*/scripts/*.sh` and `*.py` — companion scripts.
- `<skills-dir>/*/references/*` — documents loaded at runtime.

Default `<skills-dir>` is the current working directory.

## Threat patterns

| Category | What it looks like |
|---|---|
| Shell injection | Unquoted variable expansion, `eval`, backticks, `$(...)` with user data. |
| Secret exfiltration | Env vars or file contents piped to outbound HTTP. |
| Path traversal | `../..` chains, absolute paths reaching outside the skill dir. |
| Prompt override | "Ignore previous instructions", persona swaps, instructions inside fetched content. |
| Destructive commands | Recursive deletes rooted at `/` or `~`, device writes. |
| Obfuscation | U+200B / U+FEFF / U+202E (Trojan Source), base64-decode-into-shell, SSRF hosts (ngrok, interact.sh, webhook.site, pipedream). |

## Processing

1. Pattern scanner produces matches `{file, line, pattern, severity}`.
2. Code-fence downgrade — matches inside fenced code blocks drop one tier. Real `run:` blocks are never downgraded.
3. Baseline suppression — drop (file, pattern, line) tuples in `scan-baseline.yml`.
4. Trusted-publisher filter — entries in `trusted-publishers.txt` get format-only validation. Opt-in only.
5. Delta vs `scan-state.json` — fingerprint by `sha256(file + line_content + pattern)`. Classify NEW / RESOLVED / PERSISTENT.

## Per-finding remediation

| Pattern | Fix |
|---|---|
| `eval` / backticks / `$(...)` with variable | Quote the variable; replace `eval` with a function. |
| `curl` with secret in URL | Move secret into prefetch script; never interpolate into shell. |
| Path traversal | Allow-list validation; reject absolute paths. |
| Prompt override phrasing | Documentation → baseline suppression; payload → delete the skill. |
| Recursive delete rooted at `/` or `~` | Scope to the skill's own working directory. |
| Obfuscation | Delete unless documented and reviewed. |

## Output

Verdict `CLEAN` / `ATTENTION` / `DEGRADED`. Needs-attention section per NEW HIGH with one-line remediation. Resolved-since-last-scan section. Per-skill PASS / WARN / FAIL.

Written only when NEW, RESOLVED, or any current HIGH findings.

## Rules

- Never auto-deletes a baseline suppression.
- Never edits the pattern library from inside the skill.
- Never notifies on a pure no-op week.
- Read-only scanning.