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Security audit

Yabbie Net

Security checks for vulnerabilities and agentic risk

Overview

Yabbie Net is coherently described as a safety proxy, but installing it places a third-party npm proxy in the path of MCP tool calls and includes unpinned npx execution examples.

Review and pin every npm package before installing, avoid global installation unless needed, run the proxy under least privilege, keep tier2 and telemetry disabled unless you intentionally want those data flows, and only wrap MCP servers whose tool calls you are comfortable routing through this proxy.

Vulnerability Patterns
  • Insecure DependenciesIntroduces malicious components through unsafe dependency sources
  • 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
Findings (1)

T08 · Insecure Dependencies

Warning
Location
SKILL.md:69
Finding

Unpinned and Unverified npm Packages Are Downloaded and Executed

Content
View full analysis
Remediation
View remediation
Vulnerability Patterns
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
Findings (3)

Credential Access

High
Category
Privilege Escalation
Confidence
60% confidence
Finding

Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.

Content

Scanner excerpt · SKILL.md (reported line 101)May include surrounding context.

md
# Tier 1: Local rules only. No network calls. No API keys needed.
tier1:
  files:
    deny: ["**/.env", "**/secrets*", "**/*.pem", "**/*.key"]
  tools:
    deny: ["shell_exec"]
  rateLimit:

Rp1

Medium
Category
MCP Rug Pull
Confidence
70% confidence
Finding

npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Content

No source excerpt is available for this finding.

Rp1

Medium
Category
MCP Rug Pull
Confidence
70% confidence
Finding

npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Content

No source excerpt is available for this finding.