BigMailer

• Outcome: Review
• Latest audit: Nov 3, 2026 · 11:10 AM UTC
• Version: 1.0.5

Overview

BigMailer changes require approval, but the dependency setup can execute changing remote code and introduce additional agent skills without explaining those effects.

Review and install the CLI deliberately before use, and understand that BigMailer data passes through OOMOL. The publisher documents OO_SKILLS_SYNC_DISABLED=1 to prevent startup skill synchronization; configure it before invoking oo if those additional installations are unwanted. Keep the skill's write and deletion approvals. Exact remote installer behavior remains unverified.

A.I.G

Vulnerability Patterns

• Skill Instruction Hijacking: Alters the agent's session goals or safety constraints when the skill loads
• Agent Memory Poisoning: Writes attacker-controlled rules into memory that affect later sessions
• Remote Payload Retrieval and Execution: Fetches external code whose behavior can change after review
• Embedded Malicious Code: Ships malicious scripts inside the skill and executes them locally
• Unauthorized Access and Privilege Escalation: Obtains permissions beyond the task's legitimate needs

SkillSpector

Vulnerability Patterns

• Supply Chain: Unpinned Dependencies, External Script Fetching, Obfuscated Code
• Excessive Agency: Unrestricted Tool Access, Autonomous Decision Making, Scope Creep
• MCP Tool Poisoning: Hidden Instructions, Unicode Deception, Parameter Description Injection
• Prompt Injection: Instruction Override, Hidden Instructions, Exfiltration Commands
• Data Exfiltration: External Transmission, Env Variable Harvesting, File System Enumeration

Findings (3)

Description-Behavior Mismatch

High

• Category: MCP Tool Poisoning
• Confidence: 97% confidence

Finding

The supplied code performs remote installer execution rather than any visible BigMailer operation. Installation can be a supporting implementation detail, but this chunk provides no evidence that the Oomol installer supports the declared BigMailer functionality. The downloaded script's contents and further effects cannot be determined from the supplied code.

Content

No source excerpt is available for this finding.

External Script Fetching

High

• Category: Supply Chain
• Confidence: 98% confidence

Finding

The setup instructions pipe a remotely fetched script directly into Bash, and the adjacent PowerShell alternative similarly executes downloaded content without integrity verification. A compromised distribution endpoint or altered installer could execute arbitrary code with the invoking user's permissions, potentially accessing local secrets or modifying files. The legitimate dependency relationship and missing-CLI prerequisite limit when this occurs but do not make the downloaded code trustworthy.

Content

Scanner excerpt · SKILL.md (reported line 67)May include surrounding context.

• oo: command not found — install the oo CLI (other platforms: https://cli.oomol.com/install-guide.md):

  bash

  curl -fsSL https://cli.oomol.com/install.sh | bash    # macOS / Linux
  

  powershell

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 88)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