Security audit

TOEFL

Security checks for vulnerabilities and agentic risk

Overview

This TOEFL study skill stores study progress locally as part of its stated purpose and does not show hidden, destructive, or credential-seeking behavior.

Before installing, be aware that the skill is designed to keep TOEFL goals, scores, target schools, study sessions, practice results, vocabulary, and feedback in local files under ~/toefl/ or ~/toefl-tutor/. Use it on a trusted device and review or delete those files if you do not want that information retained.

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

Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
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 (3)

Missing User Warnings

Medium

Confidence: 95% confidence
Finding: The skill explicitly instructs persistent storage of user profile, study history, test dates, target schools, and feedback under ~/toefl/ without any notice, consent flow, retention limits, or privacy safeguards. While this is not overtly malicious, it creates unnecessary exposure of sensitive educational and planning data on disk, especially on shared or unmanaged systems, and may surprise users who expect ephemeral assistant interactions.

Vague Triggers

Medium

Confidence: 93% confidence
Finding: The 'Update Triggers' table uses generic events like 'Weekly', 'Section improved', and 'Score received' without defining exact trigger phrases, scope, or negative examples. In a skill context, these broad conditions could cause unintended invocation because it is unclear when an update should or should not occur.

Missing User Warnings

Low

Confidence: 83% confidence
Finding: The document explicitly instructs updating files under a user-home path (~/toefl/sections/) without warning that this alters local data. Even though this is only study-planning content, agentic systems may translate such instructions into file writes, causing unintended modification of user files or directories.

Static analysis

No suspicious patterns detected.