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Security audit

Omnisend

Security checks for vulnerabilities and agentic risk

Overview

The Omnisend workflow is clearly scoped, but its fallback setup executes unverified remote code without a separate approval step.

Review and approve CLI installation separately, using a verified release where possible. Check its automatic skill installation and synchronization settings before running it. Connecting Omnisend entrusts OOMOL with account access and contact operations; keep permissions narrow and retain the documented confirmations. Only the bundled instructions were fully inspectable; the remote installers and hosted connector implementation remain 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 code performs no visible Omnisend operations. Its sole action is to fetch and execute an Oomol installation script, which is not described by the declared purpose or shown to be a supporting dependency. The remote script's contents are unavailable, so its additional behavior cannot be assessed.

Content

No source excerpt is available for this finding.

External Script Fetching

High
Category
Supply Chain
Confidence
96% confidence
Finding

Piping a live HTTPS response directly into bash executes mutable remote code with the agent process's local privileges, without an independent integrity check or review. Although the URL is consistent with the documented CLI provider and execution is conditional on missing software, compromise of the distribution endpoint could expose local credentials or permit arbitrary system changes; the PowerShell installation example has the same underlying risk.

Content

Scanner excerpt · SKILL.md (reported line 63)May include surrounding context.

The setup workflow executes remotely downloaded installation scripts without warning about local system changes or obtaining approval.

Medium
Category
Output Handling
Confidence
94% confidence
Finding

When the CLI is missing, the setup instructions direct installation without requiring approval for executing downloaded code or modifying the local environment. Limiting setup to an actual missing-command error reduces exposure, but permission to perform Omnisend operations does not necessarily authorize software installation; the confirmation requirements elsewhere cover Omnisend data changes, not local setup.

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 84)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