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Security audit

Luckin Coffee

Security checks for vulnerabilities and agentic risk

Overview

Review before installing: setup can run downloaded software, and the required CLI can make broader changes to agent skills that this skill does not explain.

Review and approve the CLI installation separately, and control its automatic skill synchronization before use. Connect only the intended Luckin Coffee account and retain order confirmations. The bundled instructions show no malicious intent, but downloaded installer behavior and hosted connector internals 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
99% confidence
Finding

The supplied code executes a remote installation script, with no visible connection to Luckin Coffee or evidence that the installation supports the declared functionality. This is a materially different operation involving an inconsistent resource. The downloaded script's contents are not supplied, so its further effects cannot be determined.

Content

No source excerpt is available for this finding.

External Script Fetching

High
Category
Supply Chain
Confidence
98% confidence
Finding

The command executes the current contents of a remote script without version pinning or independent integrity verification; the PowerShell alternative has the same property. If the provider's distribution infrastructure is compromised, malicious code could run with the invoking user's permissions and access local files or credentials; HTTPS and the legitimate dependency relationship do not eliminate that supply-chain risk.

Content

Scanner excerpt · SKILL.md (reported line 62)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 directs the agent to execute a remote installer without first obtaining approval for executing code and changing the local environment. Restricting setup to an actual missing-command error reduces exposure, but a user's request to operate a coffee account does not necessarily authorize software installation.

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