T09 · Insecure Skill Coding Practices
Warning
- Location
references/api.md:21- Finding
Phone Number Exposed in a GET Request Query String
- Content
View full analysis
- Remediation
View remediation
Security audit
WhatsApp Number Checker
Security checks for vulnerabilities and agentic risk
Overview
This skill does what it says by checking a phone number with an external WhatsApp-check API, but users should know queried numbers are sent to that provider.
Use this skill only when you are comfortable sending the queried phone number to wa-check-api.whatsabot.com or the configured MCP service. Avoid checking numbers without authorization or doing bulk enumeration, keep the API key in a protected secret store, and prefer deployments with clear retention, redaction, and abuse-control policies.
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)
Vulnerability Patterns
- Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
- Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
- Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
- Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
- Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
Findings (3)
Vague Triggers
Medium
- Category
- Not specified by scanner
- Confidence
- 86% confidence
- Finding
The manifest and body say to use the skill when the user asks to check whether a number 'has WhatsApp' or 'is using WhatsApp,' with several example phrasings but no explicit boundaries or negative examples. This can cause unintended invocation for general conversational mentions of WhatsApp and does not specify when the skill should not activate.
- Content
Missing User Warnings
Medium
- Category
- Not specified by scanner
- Confidence
- 94% confidence
- Finding
The skill instructs sending a user-supplied phone number to an external third-party API without warning about the data disclosure or obtaining informed consent. Because phone numbers are personal data, silently transmitting them can create privacy, compliance, and trust risks, especially in environments where users may assume processing is local.
- Content
Missing User Warnings
Medium
- Category
- Not specified by scanner
- Confidence
- 94% confidence
- Finding
This API reference documents sending phone numbers to a third-party service to determine whether they are registered on WhatsApp, but it provides no privacy, consent, retention, or lawful-use guidance. Phone numbers are personal data, and exposing a lookup workflow without data-handling warnings increases the risk of unauthorized enumeration, privacy violations, and noncompliant processing under applicable privacy laws or platform policies.
- Content
Static analysis
No suspicious patterns detected.