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Security audit

Chattermill

Security checks for vulnerabilities and agentic risk

Overview

The Chattermill operations have clear approval safeguards, but setup directs the agent to execute unverified remote installation code without a separate approval step.

Review and install the CLI yourself before allowing this skill to run. Check the installer, release integrity, and automatic installation of other agent skills. OOMOL will broker access to your connected Chattermill account; use appropriately limited access and retain the required write/delete confirmations. Remote installer behavior remains unverified.

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
Vulnerability Patterns
  • Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
  • Output HandlingUnvalidated Output Injection, Cross-Context Output, Unbounded Output
  • MCP Tool PoisoningHidden Instructions, Unicode Deception, Parameter Description Injection
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
Findings (4)

Description-Behavior Mismatch

High
Category
MCP Tool Poisoning
Confidence
98% confidence
Finding

The supplied command executes an installer hosted on an Oomol domain, with no visible connection to Chattermill. Nothing in the chunk establishes this installation as a supporting dependency for the declared functionality. The downloaded script is not supplied, so its additional behavior cannot be assessed.

Content

No source excerpt is available for this finding.

External Script Fetching

High
Category
Supply Chain
Confidence
98% confidence
Finding

The curl-to-bash command executes a mutable remote script without a pinned version or independent integrity verification; the PowerShell alternative follows the same download-and-execute pattern. HTTPS protects transport but does not prevent a compromised distribution endpoint from serving code that can access local files and credentials with the user's privileges.

Content

Scanner excerpt · SKILL.md (reported line 76)May include surrounding context.

Fallback setup executes remotely downloaded installation scripts without warning about system changes or obtaining approval.

Medium
Category
Output Handling
Confidence
95% confidence
Finding

The fallback directs installation after a missing-command error without requiring approval for executing downloaded code or modifying the local environment. Although this is a legitimate dependency and a conditional path, it expands a Chattermill data request into host-level code execution with the invoking user's privileges.

Content

No source excerpt is available for this finding.

Autonomous Decision Making

Medium
Category
Excessive Agency
Confidence
80% confidence
Finding

Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.

Content

Scanner excerpt · SKILL.md (reported line 97)May include surrounding context.

md
- **`OOMOL_INSUFFICIENT_CREDIT`** — OOMOL billing stop. Recharge at `https://console.oomol.com/billing/token-recharge` before retrying.

- **HTTP 402 without `OOMOL_INSUFFICIENT_CREDIT`** — the third-party account itself has no active plan or credit. Report the provider error message as is; do not ask the user to recharge OOMOL.

## Resources