Back to skill

Security audit

Teamup Calendar

Security checks for vulnerabilities and agentic risk

Overview

Calendar operations have sensible safeguards, but setup can execute changing remote software without clear approval and may introduce broader agent changes.

Review and install the CLI separately before using this skill, including its automatic agent-skill installation and synchronization. Understand that OOMOL mediates calendar access, and retain confirmation for changes and deletions. The remote installers were unavailable for inspection; no malicious behavior 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 (4)

Description-Behavior Mismatch

High
Category
MCP Tool Poisoning
Confidence
97% confidence
Finding

The supplied chunk performs remote software installation rather than Teamup Calendar operations. Nothing shown establishes that this installer is a supporting dependency for the declared calendar functionality. The downloaded script's contents and further effects are not available for assessment.

Content

No source excerpt is available for this finding.

External Script Fetching

High
Category
Supply Chain
Confidence
97% confidence
Finding

Piping an HTTPS response directly into bash executes mutable remote content with the invoking user's privileges, without a pinned artifact or independent integrity verification. Compromise of the distribution endpoint or installer could therefore lead to local code execution and access to user-readable data; the PowerShell alternative has the same underlying risk, although there is no evidence the current installers are malicious.

Content

Scanner excerpt · SKILL.md (reported line 60)May include surrounding context.

The setup workflow executes downloaded installation scripts without warning the user about remote code execution or system changes.

Medium
Category
Output Handling
Confidence
92% confidence
Finding

The missing-CLI fallback instructs installation through immediate execution of downloaded shell or PowerShell code without requiring informed approval for local code execution and system changes. The conditional setup path and declared oo-only tool allowance reduce immediate exposure, but the installation instructions themselves lack an explicit approval gate.

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 81)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