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Security audit

Coupontools

Security checks for vulnerabilities and agentic risk

Overview

The coupon workflow has clear safeguards, but its automatic installer and undisclosed changes to other agent skills warrant review.

Prefer an already reviewed CLI installation. Require approval before running the remote installer, and review or disable its automatic agent-skill synchronization. Connecting Coupontools gives OOMOL access to the selected account; retain the skill's confirmation requirement for coupon changes. The remote installer and CLI implementation were not verified.

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
97% confidence
Finding

The only supplied command executes an external installer rather than reading or modifying Coupontools data. Although dependency installation can be a supporting implementation detail, this chunk provides no evidence that the Oomol CLI supports the declared Coupontools functionality. The downloaded script's contents and any 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 command streams a mutable remote script directly into Bash without pinning a version or verifying its integrity; the PowerShell example uses an equivalent download-and-execute pattern. Although the endpoint is relevant to the documented CLI dependency, compromise of the distribution source could execute arbitrary code with the invoking user's privileges, potentially exposing accessible credentials and files.

Content

Scanner excerpt · SKILL.md (reported line 57)May include surrounding context.

First-time setup executes remotely downloaded installation scripts without warning about their system-level effects.

Medium
Category
Output Handling
Confidence
95% confidence
Finding

The setup fallback directs the agent to install software when the CLI is missing, without requiring approval or explaining that downloaded code will run with the invoking user's privileges and may change the local environment. Restricting installation to a missing-dependency error reduces exposure, but a request to operate Coupontools does not necessarily authorize local software installation.

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 78)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