Security audit

EU ebook accessibility

Security checks for vulnerabilities and agentic risk

Overview

The skill is purpose-aligned, but it needs review because installation is mutable and the configured remote MCP can receive complete EPUB files under implicit invocation.

Install only if you are comfortable with the PowMCP service receiving the EPUB you ask it to check. Avoid confidential, embargoed, or unpublished files unless you have approval to use the external service; use the documented local DAISY Ace path for sensitive artifacts. Prefer a pinned or verified installer/source revision instead of the mutable npx command.

A.I.G

Vulnerability Patterns

Insecure DependenciesIntroduces malicious components through unsafe dependency sources
Insecure Skill Coding PracticesFinds exploitable flaws such as hardcoded secrets or command injection
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

Findings (2)

T08 · Insecure Dependencies

Error

Location: SKILL.md:34
Finding: Unpinned Package Retrieval and Execution
Content: View full analysis
Remediation: View remediation
...`. 2. Pin the Skill source to an immutable commit hash or signed release tag rather than the mutable `powmcp/skills` reference. 3. Publish and verify cryptographic checksums or signatures for downloaded artifacts. 4. Use lockfiles where supported and require integrity metadata for all transitive dependencies. 5. Avoid automatic execution of newly downloaded packages. Prefer a separate download-and-verify step before installation. 6. Document the expected package publisher, repository revision, checksum, and verification procedure. 7. Run installation in a sandbox or least-privileged environment without unnecessary credentials or access to sensitive projects. ]]>

T09 · Insecure Skill Coding Practices

Warning

Location: SKILL.md:73
Finding: Disclosure of Complete Release EPUBs to a Third-Party MCP Service
Content: View full analysis
Remediation: View remediation

SkillSpector

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 (2)

Rp1

Medium

Category: MCP Rug Pull
Confidence: 93% confidence
Finding: The skill instructs users to run npx skills add powmcp/skills --skill substantiate-eu-ebook-accessibility-claim without pinning an exact package version. npx resolves and executes the latest published package by default, so a compromised upstream release or supply-chain takeover could cause users to run attacker-controlled code during setup.
Content: No source excerpt is available for this finding.

Vague Triggers

Medium

Category: Not specified by scanner
Confidence: 92% confidence
Finding: The skill enables implicit invocation without defining trigger constraints or exclusions, so the agent may automatically call an external MCP service based on loosely related user requests. Because this tool sends content to a remote endpoint over HTTP and is intended for approval-related accessibility decisions, unintended invocation could expose EPUB content or metadata and trigger unreviewed external actions.
Content: No source excerpt is available for this finding.