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Security audit

harristeeter-mcp

Security checks for vulnerabilities and agentic risk

Overview

The skill is marked suspicious because scanners report that a grocery-shopping skill also offers prescription access, including retrieval of records across linked patient profiles.

Consider the suspicious verdict and the reported access to sensitive prescription information, including records for linked patients, before installing. The scan is incomplete: one executable script was only partially inspected, and a tool-misuse analysis was degraded.

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
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
  • MCP Tool PoisoningHidden Instructions, Unicode Deception, Parameter Description Injection
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
Findings (4)

Description-Behavior Mismatch

High
Category
MCP Tool Poisoning
Confidence
98% confidence
Finding

The grocery-focused activation description does not disclose prescription access, a materially different and sensitive capability available through the same skill. Coupons, recipes, and related shopping features are reasonable extensions, but pharmacy access expands the privacy boundary; its explicit documentation and separate sign-in reduce, rather than eliminate, that concern.

Content

No source excerpt is available for this finding.

The skill exposes prescription records for every linked patient profile, outside its stated grocery-shopping purpose.

High
Category
Excessive Agency
Confidence
99% confidence
Finding

The rx command enumerates every linked patient profile and prints prescription identifiers, drug names, refill information, and other medical details without patient selection or output minimization. This can expose family members' sensitive health information unnecessarily to the agent and its output consumers; the pharmacy-session check prevents unauthenticated access but does not constrain retrieval to the user's requested patient or information.

Content

No source excerpt is available for this finding.

The skill exposes prescription access outside its stated grocery-shopping purpose.

Medium
Category
Excessive Agency
Confidence
94% confidence
Finding

The instructions make prescription retrieval available within a grocery-oriented skill without requiring an explicit health-data authorization decision. Separate pharmacy authentication is a useful safeguard, but an existing authenticated session does not by itself establish consent for an agent to retrieve medical information.

Content

No source excerpt is available for this finding.

The request reference includes access to personal customer-profile data outside the stated shopping capabilities.

Medium
Category
Excessive Agency
Confidence
88% confidence
Finding

L49 documents a customer-profile GET endpoint and explicitly acknowledges that it contains personal data. Reading the customer's personal profile is not among the manifest's declared shopping operations, and the reference already obtains the required store context through modality preferences without this endpoint.

Content

No source excerpt is available for this finding.