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Security audit

Vapi

Security checks for vulnerabilities and agentic risk

Overview

Review is recommended because setup runs unverified downloaded code and the safety rules incorrectly treat code execution as read-only.

Before installing, review and verify the CLI installer and control its automatic skill synchronization. Require approval of the exact code and expected effects before using the code-execution action. OOMOL mediates access to your connected Vapi account. The bundled instructions were fully inspected, but installer contents and remote sandbox behavior remain unverified; no malicious intent was established.

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 (6)

Description-Behavior Mismatch

High
Category
MCP Tool Poisoning
Confidence
99% confidence
Finding

The supplied command performs remote installer execution rather than Vapi data operations. Nothing in the supplied chunk establishes that the Oomol installer is a supporting dependency for Vapi, so this is an undeclared capability involving an inconsistent resource. The downloaded script's further behavior cannot be determined from the supplied code.

Content

No source excerpt is available for this finding.

Description-Behavior Mismatch

High
Category
MCP Tool Poisoning
Confidence
86% confidence
Finding

The supplied chunk performs only a CLI login rather than the declared Vapi functionality. Authentication could be a supporting implementation detail if oo were established as a Vapi integration, but the supplied content provides no such connection. This assessment is limited to the shown chunk.

Content

No source excerpt is available for this finding.

External Script Fetching

High
Category
Supply Chain
Confidence
99% confidence
Finding

Piping the HTTPS download directly into bash executes mutable remote content without verifying a fixed, trusted artifact. HTTPS protects transport but not against compromise of the publisher or distribution infrastructure; this is the same underlying installation risk identified by SQP-2, not an independent attack path.

Content

Scanner excerpt · SKILL.md (reported line 92)May include surrounding context.

The untagged code-execution action contradicts the claim that all untagged actions are read-only.

Medium
Category
Excessive Agency
Confidence
97% confidence
Finding

The untagged test_code_tool_execution action executes TypeScript, contradicting the blanket assertion that untagged actions are read-only and safe to run directly. This classification can cause an agent to bypass confirmation for code execution; the stated Vapi sandbox limits the demonstrated scope, but execution costs and any sandbox-permitted side effects remain possible.

Content

No source excerpt is available for this finding.

Fallback setup executes downloaded installation scripts without warning the user about remote-code execution.

Medium
Category
Output Handling
Confidence
97% confidence
Finding

The fallback directs the agent to execute remotely downloaded shell or PowerShell code without an explicit installation approval or artifact-verification step. Although this occurs only when the CLI is missing and serves a legitimate dependency need, a compromised installation source could execute arbitrary code with the agent's local permissions.

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 113)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