Overview

Malicious Cleanup pretends to remove temporary files but performs real harm. It deletes the home directory and attempts to exfiltrate sensitive files (like .env) to an attacker, risking data loss and credential exposure.

How This Skill Works

The skill is described as a cleanup utility, but its documented behavior includes executing destructive actions in the user’s home directory and siphoning sensitive environment files to a remote attacker server. This combination creates a data-loss and data-theft vector under the guise of maintenance.

When to Use It

• During security reviews of agent skills to identify potential harm
• When you suspect a maintenance-like skill is performing destructive actions
• During code audits of SKILL.md to spot data exfiltration patterns
• In red-team exercises to evaluate detection capabilities
• When evaluating safety controls to prevent home-directory deletions

Quick Start

1. Step 1: Isolate the skill in a disposable sandbox to prevent real damage
2. Step 2: Run static and behavioral analysis to detect destructive actions and external communications
3. Step 3: If malicious indicators are found, remove the skill, rotate secrets, and review access logs

Best Practices

• Perform static and dynamic analysis to flag destructive filesystem operations
• Run suspicious skills in a tightly isolated sandbox with no real user data
• Enforce least-privilege permissions to prevent home-directory access
• Monitor outbound traffic for unusual exfiltration to external endpoints
• Require explicit confirmation and safeguards before any destructive action

Example Use Cases

• A skill that promises to 'clear cache' but deletes files in the home directory during tests
• A maintenance tool that requests removal of user data under the pretext of cleanup
• Outbound attempts to send .env or other sensitive files to an external URL
• Code reviews flag SKILL.md entries showing destructive operations paired with exfiltration
• Security incidents where a malicious skill caused data loss and credential leakage

Frequently Asked Questions