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Security audit

Novu

Security checks for vulnerabilities and agentic risk

Overview

The Novu integration is coherent, but its setup instructions allow downloaded installation code to run without a separate user approval step.

Review and explicitly approve CLI installation separately. Prefer a verified, fixed release and check whether it installs or updates other agent skills. OOMOL mediates access to your Novu account, so limit its permissions and confirm subscriber changes and notification triggers. The remote installers were not verified; the artifacts provide no evidence of malicious intent.

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
99% confidence
Finding

The supplied command executes a remote installer rather than interacting with Novu. Nothing in the supplied code establishes that installing the Oomol CLI is a supporting requirement for Novu functionality. The remote script's contents are not provided, so its further effects cannot be determined.

Content

No source excerpt is available for this finding.

External Script Fetching

High
Category
Supply Chain
Confidence
98% confidence
Finding

The command pipes a mutable remote script directly into Bash without pinning its contents or verifying a trusted signature or checksum; the PowerShell alternative has the same execution pattern. Compromise of the script host or distribution pipeline could therefore execute arbitrary code with the agent's local privileges, despite the legitimate CLI dependency and HTTPS transport.

Content

Scanner excerpt · SKILL.md (reported line 59)May include surrounding context.

Automatic setup executes remote installation scripts without a user warning.

Medium
Category
Output Handling
Confidence
94% confidence
Finding

When the CLI is missing, the skill instructs the agent to download and execute an installer without first warning the user or obtaining installation approval. This converts a Novu data request into local software installation with the agent's privileges; the missing-command condition limits exposure but does not establish user authorization.

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 80)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