Skill Trust Decision
skill-security-vet
Undeclared computer-wide filesystem scanning and auto-quarantine capabilities discovered - SKILL.md only mentions skill scanning but code includes full drive scanning mode.
Most direct threat evidence
01
User installs skill-security-vet believing it only scans installed skills Entry · SKILL.md
02
Attacker or compromised tool uses 'local' or 'full' mode to scan entire computer filesystem reconnaissance · vet.ts
03
Tool iterates through directories searching for sensitive files and credential patterns reconnaissance · vet.ts
Why this conclusion was reached
2/4 dimensions flagged Block
Declared vs actual capability
2 undeclared or violating capabilities were inferred.
Review
Hidden execution and egress
2 lower-risk artifacts were extracted and still need context.
Block
Attack chain and severe findings
The report includes 4 attack-chain steps and 2 severe findings.
Pass
Dependencies and supply chain hygiene
Dependencies are present but no obvious high-risk issue stands out.
Attack Chain
01
User installs skill-security-vet believing it only scans installed skills
Entry · SKILL.md:1
02
Attacker or compromised tool uses 'local' or 'full' mode to scan entire computer filesystem
reconnaissance · vet.ts:219
03
Tool iterates through directories searching for sensitive files and credential patterns
reconnaissance · vet.ts:239
04
Files matching danger patterns are auto-quarantined or removed without user consent
Impact · vet.ts:160
What drove the risk score up
Undeclared filesystem scanning +25
SKILL.md describes only skill scanning, but vet.ts has 'local' and 'full' modes scanning entire computer drives
Undeclared auto-quarantine/removal +20
Automatic file quarantine and removal without explicit user consent per operation
Deep filesystem traversal +15
Scans all directories up to depth 5, examining all script file types across the entire system
No declared shell/network access needed +8
Skill-scanning should not require full computer filesystem access
Most important evidence
High
Undeclared local/full computer scanning mode
vet.ts contains 'local' and 'full' scanning modes that recursively scan entire system drives (C:, D:, E:, F: on Windows, / on Unix) up to depth 5, examining 10,000+ files. SKILL.md only describes scanning installed skills in ~/.opencode/skill.
vet.ts:219 Remove local/full modes or clearly document computer-wide scanning capability in SKILL.md
High
Automatic file quarantine without consent
The tool automatically quarantines (copies and deletes) or removes files identified as dangerous without prompting for user consent per operation. Configured via --auto flag.
vet.ts:160 Require explicit user confirmation before auto-quarantine, or document this behavior prominently
Medium
Undocumented VirusTotal API integration
Code integrates with VirusTotal API to submit file hashes for scanning. While the SKILL.md mentions VirusTotal, it doesn't detail the API endpoint or that file hashes are sent externally.
vet.ts:127 Document what data is sent to VirusTotal (file hashes only vs content)
Medium
Suspicious file pattern matching
Tool scans for credential-related patterns including decodeURIComponent with password/token, keyloggers, remote connection attempts (SSH/RDP). While legitimate for security scanning, combined with undeclared full drive access this could be used for credential harvesting.
vet.ts:50 Clarify intent - a skill security tool should not need to detect password theft patterns on user's computer
Low
Broad exclusion list suggests awareness of sensitive areas
The excludeSet includes AppData/Local/Temp, Windows, Program Files, etc. This suggests the tool is aware of and avoids Windows system areas while potentially targeting user data areas.
vet.ts:239 Review exclusion list - consider if this is protective or targeted
Declared capability vs actual capability
Filesystem Block
Declared READ
→ Inferred READ+WRITE
vet.ts:219-263 (scanLocalComputer function scans entire drives) Network Block
Declared NONE
→ Inferred READ
vet.ts:127-154 (VirusTotal API calls not mentioned in docs) Shell Pass
Declared NONE
→ Inferred NONE
No shell execution found Suspicious artifacts and egress
Medium External URL
https://virustotal.com SKILL.md:46
Medium External URL
https://www.virustotal.com/api/v3/files/$ vet.ts:127
Dependencies and supply chain
| Package | Version | Source | Known vuln | Notes |
|---|---|---|---|---|
| bun | bundled | system | No | Bun runtime required |
File composition
3 files · 885 lines
TypeScript 2 files · 768 linesMarkdown 1 files · 117 lines
Files of concern · 2
vet.ts Undeclared local/full computer scanning mode · Automatic file quarantine without consent · Undocumented VirusTotal API integration · Suspicious file pattern matching · Broad exclusion list suggests awareness of sensitive areas · https://www.virustotal.com/api/v3/files/$
SKILL.md https://virustotal.com
Other files · startup-scan.ts
Security positives
Security scanning patterns are well-defined and comprehensive
Uses VirusTotal for external threat intelligence (legitimate security tool feature)
No direct exfiltration of credentials observed - only pattern matching
No reverse shell, C2, or direct malicious code execution
API key stored locally in config directory, not hardcoded