Security audit

Poyo Claude Fable 5

Security checks for vulnerabilities and agentic risk

Overview

This skill is a disclosed PoYo API integration that sends user-prepared message payloads to PoYo only for the stated model workflow.

Install this only if you intend to use PoYo's Claude Fable 5 API. Treat POYO_API_KEY as a server-side secret and review each JSON payload before submitting, because messages, system prompts, tool definitions, image content, and other payload data will be sent to PoYo when the script or curl examples are used.

A.I.G

Vulnerability Patterns

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
Unauthorized Access and Privilege EscalationObtains permissions beyond the task's legitimate needs

SkillSpector

Vulnerability Patterns

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

Findings (12)

Credential Access

High

Category: Privilege Escalation
Content: Content-Type: application/json ``` Get API keys from <https://poyo.ai/dashboard/api-key>. Recommended skill env var:
Confidence: 70% confidence
Finding: Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.

Lp3

Medium

Category: MCP Least Privilege
Confidence: 79% confidence
Finding: The skill advertises shell-capable execution via required `curl` usage and references an executable script, but it does not declare any explicit tool scope such as `permissions` or `allowed-tools`. That omission weakens least-privilege controls and can let an agent invoke broader shell functionality than the skill description strictly requires, increasing the chance of unintended command execution or secret exposure.

External Transmission

Medium

Category: Data Exfiltration
Content: ## Basic Messages Example ```bash curl --fail-with-body --request POST \ --url "https://api.poyo.ai/v1/messages" \ --header "x-api-key: YOUR_API_KEY" \ --header "anthropic-version: 2023-06-01" \
Confidence: 60% confidence
Finding: Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

External Transmission

Medium

Category: Data Exfiltration
Content: : "${POYO_API_KEY:?POYO_API_KEY is required}" curl --fail-with-body --request POST \ --url "https://api.poyo.ai/v1/messages" \ --header "x-api-key: ${POYO_API_KEY}" \ --header "anthropic-version: 2023-06-01" \
Confidence: 70% confidence
Finding: Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Missing User Warnings

Medium

Confidence: 91% confidence
Finding: This shell script sends the contents of a user-supplied JSON file to a remote service using curl, which is a network operation that may transmit user or system data. The script provides no confirmation prompt, logging, or inline comment/docstring warning the user that the payload file will be sent externally.

External Transmission

Medium

Category: Data Exfiltration
Content: : "${POYO_API_KEY:?POYO_API_KEY is required}" curl --fail-with-body --request POST \ --url "https://api.poyo.ai/v1/messages" \ --header "x-api-key: ${POYO_API_KEY}" \ --header "anthropic-version: 2023-06-01" \ --header "Content-Type: application/json" \
Confidence: 60% confidence
Finding: Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

External Transmission

Medium

Category: Data Exfiltration
Content: : "${POYO_API_KEY:?POYO_API_KEY is required}" curl --fail-with-body --request POST \ --url "https://api.poyo.ai/v1/messages" \ --header "x-api-key: ${POYO_API_KEY}" \ --header "anthropic-version: 2023-06-01" \ --header "Content-Type: application/json" \
Confidence: 60% confidence
Finding: Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

External Transmission

Medium

Category: Data Exfiltration
Content: : "${POYO_API_KEY:?POYO_API_KEY is required}" curl --fail-with-body --request POST \ --url "https://api.poyo.ai/v1/messages" \ --header "x-api-key: ${POYO_API_KEY}" \ --header "anthropic-version: 2023-06-01" \ --header "Content-Type: application/json" \
Confidence: 60% confidence
Finding: Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

External Transmission

Medium

Category: Data Exfiltration
Content: : "${POYO_API_KEY:?POYO_API_KEY is required}" curl --fail-with-body --request POST \ --url "https://api.poyo.ai/v1/messages" \ --header "x-api-key: ${POYO_API_KEY}" \ --header "anthropic-version: 2023-06-01" \ --header "Content-Type: application/json" \
Confidence: 60% confidence
Finding: Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

External Transmission

Medium

Category: Data Exfiltration
Content: : "${POYO_API_KEY:?POYO_API_KEY is required}" curl --fail-with-body --request POST \ --url "https://api.poyo.ai/v1/messages" \ --header "x-api-key: ${POYO_API_KEY}" \ --header "anthropic-version: 2023-06-01" \ --header "Content-Type: application/json" \
Confidence: 60% confidence
Finding: Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

External Transmission

Medium

Category: Data Exfiltration
Content: : "${POYO_API_KEY:?POYO_API_KEY is required}" curl --fail-with-body --request POST \ --url "https://api.poyo.ai/v1/messages" \ --header "x-api-key: ${POYO_API_KEY}" \ --header "anthropic-version: 2023-06-01" \ --header "Content-Type: application/json" \
Confidence: 60% confidence
Finding: Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Missing User Warnings

Low

Confidence: 77% confidence
Finding: The script requires and accesses the POYO_API_KEY environment variable, which is a sensitive credential. Although the variable is validated for presence, there is no comment or user-facing notice explaining that the script consumes an API key for authentication to an external service.

Static analysis

No suspicious patterns detected.