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Security audit

Cold Email Outreach

Security checks for vulnerabilities and agentic risk

Overview

This skill is not clearly malicious, but it enables cold-email automation with overstated capabilities, weak guardrails, and a sending bug that could cause unintended emails.

Review carefully before installing. This skill can send real cold emails through your Resend account and process recipient contact data, while some advertised pipeline features are not actually present. Use dry-run first, avoid --limit 0 as a stop control, confirm you have a lawful basis for every contact, and provide working unsubscribe, bounce handling, and retention controls yourself.

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 (2)

T09 · Insecure Skill Coding Practices

Warning
Location
scripts/send-campaign.js:104
Finding

Explicit zero send limit defaults to 25 outgoing emails

Content
View full analysis
Remediation
View remediation
RATE_LIMIT) { throw new Error(`--limit must be between 0 and ${RATE_LIMIT}`); } const limit = requestedLimit; ``` Additional hardening should include automated tests for omitted, zero, negative, nonnumeric, fractional, and excessively large values. A zero limit should exit without contacting the Resend API. ]]>

T09 · Insecure Skill Coding Practices

Note
Location
scripts/send-campaign.js:56
Finding

Untrusted CSV headers are compiled into regular expressions

Content
View full analysis
h.trim()); return lines.slice(1).map(line => { const values = line.split(',').map(v => v.trim()); const obj = {}; headers.forEach((h, i) => obj[h] = values[i] || ''); return obj; }); } ``` ```js function fillTemplate(template, vars) { let text = template; for (const [key, value] of Object.entries(vars)) { text = text.replace(new RegExp(`\\{${key}\\}`, 'g'), value || ''); } return text; } ``` ### Technical Analysis CSV column names are accepted without validation and become property names in each lead object. During template expansion, every property name is interpolated directly into a dynamically constructed regular expression. Regular-expression metacharacters in a CSV header are therefore interpreted as syntax rather than literal characters. A malformed header can generate an invalid expression and throw a `SyntaxError`. A syntactically valid but specially constructed header can also alter which placeholders are matched, causing unexpected substitutions. The top-level error handler terminates the process after such an exception: ```js main().catch(e => { console.error('Campaign error:', e.message); process.exit(1); }); ``` Although this prevents arbitrary code execution, it allows a supplied lead file to disrupt campaign processing. ### Attack Path 1. An attacker, upstream lead provider, or malformed export supplies a CSV accepted as the campaign lead list. 2. The CSV contains a regex metacharacter in a header, such as: ```csv email,[,first_name victim@example.com,value,Alice ``` 3. `parseCSV()` stores `[` as an object key. 4 ...[truncated 789 chars]
Remediation
View remediation

SkillSpector

Vulnerability Patterns
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
  • MCP Least PrivilegeUnderdeclared Capability, Wildcard Permission, Missing Permission Declaration
  • MCP Tool PoisoningHidden Instructions, Unicode Deception, Parameter Description Injection
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
Findings (6)

Tp4

High
Category
MCP Tool Poisoning
Confidence
95% confidence
Finding

The skill advertises a broad automated outreach pipeline including scraping, enrichment, drip sequencing, tracking, and deliverability management, but the described implementation does not actually provide those controls. This mismatch is dangerous because users may rely on nonexistent safeguards or assume compliant handling of prospect data, resulting in privacy, spam, or operational abuse risks.

Content

No source excerpt is available for this finding.

Missing User Warnings

High
Category
Not specified by scanner
Confidence
95% confidence
Finding

The markdown promotes scraping leads, enriching contact details, and sending automated cold emails, but it omits a clear warning about privacy, consent, legal restrictions, and data-handling obligations. This is especially dangerous in a cold-outreach skill because it normalizes collection and use of personal/business contact data without guardrails, increasing the risk of privacy violations, unlawful processing, and spam abuse.

Content

No source excerpt is available for this finding.

Undeclared Tool Scope

Medium
Category
MCP Least Privilege
Confidence
89% confidence
Finding

The skill declares access to an environment variable (RESEND_API_KEY) but does not define an explicit tool or permission scope. In agent environments, missing scope declarations can cause overbroad execution privileges or unclear secret access boundaries, making it easier for a skill to access sensitive data without transparent user consent.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
96% confidence
Finding

The skill uses broad trigger language such as general outreach, prospecting, and campaign setup, which increases the chance it will be invoked for loosely related requests without meaningful user intent verification. In this context, that is risky because the skill can facilitate scraping, contact enrichment, and bulk cold-email activity that may carry legal, privacy, and anti-spam consequences.

Content

No source excerpt is available for this finding.

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · references/deliverability.md (reported line 22)May include surrounding context.

4. Verify in Resend

bash
curl -X POST https://api.resend.com/domains \
  -H "Authorization: Bearer YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"name": "yourdomain.com"}'

External Transmission

Medium
Category
Data Exfiltration
Confidence
50% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · references/deliverability.md (reported line 22)May include surrounding context.

4. Verify in Resend

bash
curl -X POST https://api.resend.com/domains \
  -H "Authorization: Bearer YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"name": "yourdomain.com"}'