Security audit

Excel Workflow

Security checks for vulnerabilities and agentic risk

Overview

This Excel skill is coherent, but it automatically uploads spreadsheets to Google Drive, modifies/re-uploads files, and keeps local tracking data without clear opt-in, retention, or deletion controls.

Install only if you are comfortable with spreadsheets being uploaded to Google Drive and tracked locally. Avoid confidential, regulated, client, or financial workbooks unless you can constrain the Google Drive permission, confirm uploads before they happen, keep backups of files before updates, and verify how to delete both the Drive copies and the local SQLite tracker.

SkillSpector

Vulnerability Patterns

Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
Rogue AgentSelf-Modification, Session Persistence
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

Findings (8)

Missing User Warnings

Medium

Confidence: 83% confidence
Finding: The README advertises automatic Google Drive syncing and backups for uploaded Excel files but does not warn that user-provided spreadsheets may contain sensitive business or personal data that will be transmitted to a third-party cloud service. In this skill context, that omission is meaningful because users may reasonably assume files are processed locally, increasing the risk of unintentional data disclosure or policy violations.

Vague Triggers

Medium

Confidence: 88% confidence
Finding: The skill is positioned for broadly defined Excel and spreadsheet tasks without strong guardrails on when it should be invoked. In context, that matters because invocation can trigger automatic cloud upload and local persistence of spreadsheet contents, so over-broad routing increases the chance of unnecessary processing of sensitive data.

Missing User Warnings

High

Confidence: 97% confidence
Finding: The quick-start flow states that dropping an .xlsx file automatically uploads it to Google Drive and stores metadata in SQLite, but it does not prominently warn users before that transfer and retention happen. This creates a meaningful privacy and data-governance risk because users may provide financial or personal spreadsheet data without informed consent to cloud sync and local tracking.

Missing User Warnings

Medium

Confidence: 91% confidence
Finding: The README advertises automatic Google Drive sync and backup but does not clearly warn users that uploaded Excel contents may be transmitted to an external third-party service. For a workflow handling potentially sensitive spreadsheets, this omission can lead to unintended data disclosure because users may enable or use the skill without understanding the privacy and compliance implications.

Missing User Warnings

Medium

Confidence: 97% confidence
Finding: The skill explicitly states that uploaded Excel files are automatically synced to Google Drive, but it does not present a clear user-facing consent or privacy warning before third-party transmission. Because spreadsheets often contain sensitive business or personal data, silent cloud upload can cause unintended data disclosure and compliance issues even if the sync is part of the advertised functionality.

Missing User Warnings

Medium

Confidence: 95% confidence
Finding: The update workflow describes changing spreadsheet contents and then re-uploading the modified file to Google Drive without an explicit warning that user data will be altered and pushed remotely. This is dangerous because users may assume a local preview/change only, while the system performs persistent modification plus third-party synchronization that could overwrite authoritative records or leak updated sensitive data.

Session Persistence

Medium

Category: Rogue Agent
Content: - ✅ **SQLite Tracking** — Track all files, formulas, and metadata in local database - ✅ **Multi-file Support** — Work with multiple Excel files simultaneously - ✅ **Data Analysis** — Query data, read formulas, and analyze structure - ✅ **Mass Operations** — Create formulas for entire columns at once ## Quick Start
Confidence: 84% confidence
Finding: The skill explicitly maintains a local SQLite tracker of files, formulas, paths, and timestamps, and supports multi-file workflows, which indicates persistence of user-derived data across sessions. In this context, persistence becomes security-relevant because spreadsheet metadata and possibly sensitive business structure are retained locally without clear minimization, consent, retention limits, or access controls.

Session Persistence

Medium

Category: Rogue Agent
Content: - ✅ **SQLite Tracking** — Track all files, formulas, and metadata in local database - ✅ **Multi-file Support** — Work with multiple Excel files simultaneously - ✅ **Data Analysis** — Query data, read formulas, and analyze structure - ✅ **Mass Operations** — Create formulas for entire columns at once ## Quick Start
Confidence: 84% confidence
Finding: The skill persistently tracks files, formulas, paths, and metadata in a local SQLite database and supports multi-file workflows, but the documentation does not define retention limits, access controls, or user consent for this stored state. Persistent storage of spreadsheet metadata can expose sensitive filenames, formulas, business logic, and workflow history to other local users, later processes, or forensic recovery.

Static analysis

No suspicious patterns detected.