Security audit

PMC Harvest

Security checks for vulnerabilities and agentic risk

Overview

The skill mostly matches its PubMed Central harvesting purpose, but it exposes broader network access than it documents.

Review before installing in environments with sensitive internal network access. Prefer a version that does not export a generic HTTP helper, restricts requests and redirects to eutils.ncbi.nlm.nih.gov and pmc.ncbi.nlm.nih.gov, and enforces request timeouts and response-size limits.

A.I.G

Vulnerability Patterns

Insecure Skill Coding PracticesFinds exploitable flaws such as hardcoded secrets or command injection
Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
Embedded Malicious CodeShips malicious scripts inside the skill and executes them locally

Findings (1)

T09 · Insecure Skill Coding Practices

Warning

Location: lib/api.js:25
Finding: Unrestricted HTTPS Requests and Unvalidated Redirect Destinations
Content: View full analysis
{ if (redirects > 5) { reject(new Error('Too many redirects')); return; } const parsedUrl = new URL(url); const options = { hostname: parsedUrl.hostname, path: parsedUrl.pathname + parsedUrl.search, method: 'GET', headers: { 'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'User-Agent': 'PMC-Harvest/1.0' } }; https.get(options, (res) => { if (res.statusCode >= 300 && res.statusCode < 400 && res.headers.location) { const location = res.headers.location; const redirectUrl = location.startsWith('http') ? location : new URL(location, parsedUrl.origin).href; return httpGet(redirectUrl, redirects + 1).then(resolve).catch(reject); } let stream = res; const encoding = res.headers['content-encoding']; if (encoding === 'gzip') { stream = res.pipe(zlib.createGunzip()); } else if (encoding === 'deflate') { stream = res.pipe(zlib.createInflate()); } let data = ''; stream.on('data', chunk => data += chunk); stream.on('end', () => { if (res.statusCode >= 200 && res.statusCode < 300) { resolve(data); } else { reject(new Error(`HTTP ${res.statusCode}`)); } }); stream.on('error', reject); }).on('error', reject); }); } ``` The unrestricted helper is also exposed as part of the public module API: ```javascript module.exports = { searchPMC, getSummaries, fetchFullText, fetchAbstract, parseJATS, harvestJournals, httpGet }; ``` ### Technical Analysis Th ...[truncated 2821 chars]
Remediation: View remediation

SkillSpector

Vulnerability Patterns

MCP Least PrivilegeUnderdeclared Capability, Wildcard Permission, Missing Permission Declaration
Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code

Findings (1)

Undeclared Tool Scope

Medium

Category: MCP Least Privilege
Confidence: 87% confidence
Finding: The skill clearly instructs users to invoke Node.js code that performs outbound network access to NCBI endpoints, but the manifest does not declare any explicit tool scope such as permissions or allowed-tools. This creates a least-privilege and transparency gap: an agent or reviewer cannot tell from the top-level declaration that executing the skill will make network requests, which can lead to unintended data egress or policy bypass in environments that rely on manifest-declared capabilities.
Content: No source excerpt is available for this finding.

Static analysis

No suspicious patterns detected.