Back to skill

Security audit

Legacy Web Standard

Security checks for vulnerabilities and agentic risk

Overview

This is a documentation-only frontend maintenance skill with coherent scope and no hidden execution, persistence, credential use, or data access behavior.

Installers should treat this as a low-risk guidance skill for legacy frontend maintenance. It may be selected for a fairly wide range of vanilla JS, jQuery, HTML/CSS, and multipage frontend work, so users who need modern framework migration, deeper security review, or validation workflows should choose a more specific skill for those tasks.

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
  • Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
  • Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
Findings (5)

Skill Enumeration

Medium
Category
Agent Snooping
Confidence
80% confidence
Finding

Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.

Content

Scanner excerpt · README.md (reported line 10)May include surrounding context.

md
- ID: `fec-legacy-web-standard`
- Category: `legacy-migration`
- Version: `2.9.0`
- Source: `skills/fec-legacy-web-standard/SKILL.md`

## Description

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
93% confidence
Finding

The README says to 'Use when maintaining or safely modifying existing non-framework frontend code' and then lists broad technologies and contexts, but it does not define specific invocation phrases, exclusions, or negative examples. This ambiguity could cause the skill to be selected for many ordinary frontend tasks beyond its intended legacy-maintenance scope.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
91% confidence
Finding

The manifest description says the skill should be used when 'maintaining or safely modifying existing non-framework frontend code' and lists Chinese triggers such as 'traditional frontend' and 'native JS'. These phrases are broad and could overlap with many ordinary frontend requests, but the manifest does not provide explicit trigger boundaries or negative examples to clarify when this skill should not activate.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
86% confidence
Finding

The description specifies 'Chinese triggers include traditional frontend, native JS, jQuery,' which introduces a language-specific trigger policy in natural language. There is no indication that language choice is optional or user-configurable.

Content

No source excerpt is available for this finding.

Vague Triggers

Low
Category
Not specified by scanner
Confidence
91% confidence
Finding

The description is broadly scoped and includes multiple loosely bounded trigger conditions such as maintaining legacy frontend code, vanilla JavaScript, jQuery, HTML/CSS, MPA pages, and server-rendered templates. In an agent-skill ecosystem, this can cause over-invocation or ambiguous routing, which may lead the skill to activate in contexts beyond its intended specialty and produce unsafe or low-quality guidance for unrelated tasks.

Content

No source excerpt is available for this finding.

Static analysis

No suspicious patterns detected.