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Security audit

Planhat

Security checks for vulnerabilities and agentic risk

Overview

The Planhat workflow has clear safeguards, but its automatic setup can execute unverified remote installers without approval for their local effects.

Review and approve CLI installation separately, preferably using a pinned, verified release. Check whether it installs or updates other agent skills. OOMOL mediates Planhat access, and changes to Planhat records should follow the skill's explicit confirmation rules. The remote installers were unavailable for inspection, so their exact local effects remain uncertain.

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
96% confidence
Finding

The supplied chunk performs remote installer execution rather than any visible Planhat operation. Dependency installation can be a supporting implementation detail, but this chunk establishes no relationship between the Oomol installer and the declared Planhat functionality. The downloaded script is not supplied, so its subsequent behavior and any Planhat integration cannot be verified.

Content

No source excerpt is available for this finding.

External Script Fetching

High
Category
Supply Chain
Confidence
97% confidence
Finding

The curl-to-Bash pipeline executes mutable remote content without a pinned version or independent integrity verification. Compromise of the installer distribution path could execute attacker-controlled code with the agent's local privileges; HTTPS and the legitimate CLI dependency reduce neither that supply-chain consequence nor the need for verification.

Content

Scanner excerpt · SKILL.md (reported line 62)May include surrounding context.

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

Medium
Category
Output Handling
Confidence
92% confidence
Finding

The setup workflow directs execution of downloaded Bash or PowerShell scripts without explaining their local effects or requiring explicit approval for installing software. Although this occurs only when the CLI is missing, a routine Planhat request could consequently lead to local code execution with the agent's privileges rather than just connector operations.

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 83)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