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Security audit

Telnyx

Security checks for vulnerabilities and agentic risk

Overview

The Telnyx workflow includes user approval for sending messages, but its setup fallback runs an unverified remote installer without a separate approval step.

Review the CLI installation before enabling this skill. Prefer a verified, pinned installation under your control, and check whether it installs or updates other agent skills. OOMOL handles the connected credentials and requests; approve that intermediary and confirm message recipients and content before sending. The bundled instructions were fully inspected, but the remote installer 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
97% confidence
Finding

The visible behavior is remote installer execution, not interaction with Telnyx. Nothing in the supplied code establishes this installer as a supporting dependency for Telnyx operations. The downloaded script's contents are not provided, so its further behavior cannot be determined.

Content

No source excerpt is available for this finding.

External Script Fetching

High
Category
Supply Chain
Confidence
98% confidence
Finding

Piping an unpinned HTTPS download directly into bash executes whatever the installation endpoint serves with the agent process's privileges. Compromise of the distribution endpoint or installer supply chain could expose accessible credentials and files or modify the host; HTTPS alone does not establish installer integrity.

Content

Scanner excerpt · SKILL.md (reported line 58)May include surrounding context.

The setup workflow instructs the agent to execute downloaded installation scripts without warning the user about remote code execution or system changes.

Medium
Category
Output Handling
Confidence
95% confidence
Finding

The fallback instructs the agent to execute remotely supplied shell or PowerShell code without first obtaining approval for local code execution and system changes. Although installation supports the legitimate Telnyx workflow and occurs only when the CLI is missing, that condition does not authorize arbitrary installer behavior on the user's machine.

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 79)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