T08 · Insecure Dependencies
Warning
- Location
README.md:38- Finding
Unpinned Third-Party Package Execution During Installation
- Content
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Vulnerability Details
File Location:
README.md:38-42
Vulnerability Type: Unpinned third-party package execution throughnpx
Risk Level: MediumVulnerable Code
markdown ## Installation ```bash npx skills add de-novo/pencil-skilltext ### Technical Analysis The documented installation command invokes `npx` without pinning the `skills` package to a reviewed version or verifying its integrity. If the package is not already available locally, `npx` may retrieve the current package release from the configured npm registry and immediately execute its command-line entry point. Consequently, the code executed during installation can differ from the code reviewed in this project. This creates a supply-chain trust boundary involving the registry, package maintainers, publisher credentials, and the user's npm configuration. The audited project itself does not contain a malicious dependency or remote-execution implementation; the risk arises from the unpinned installation guidance. ### Attack Path 1. An attacker compromises the upstream `skills` package, its maintainer account, publishing credentials, or the package source delivered by the configured registry. 2. The attacker publishes a malicious or backdoored release under the expected package name. 3. A user follows the documented command without specifying a trusted version. 4. `npx` resolves and downloads the attacker-controlled release. 5. `npx` executes the package entry point with the privileges and environment of the invoking user. 6. The malicious package can perform actions allowed to that user before or while installing the requested skill. ### Impact Assessment Successful exploitation permits arbitrary code execution with the invoking user's privileges. Depending on that user's permissions and environment, the malicious package could read or alter accessible files, steal environment-held credentials, modify development projects, t ...[truncated 297 chars]- Remediation
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Remediation Suggestions
- Pin the installer to an explicitly reviewed version:
bash npx skills@<verified-version> add de-novo/pencil-skill - Document the expected npm registry and advise users to verify that their npm configuration does not redirect package resolution to an untrusted source.
- Publish and document the expected package integrity digest or signed provenance where supported.
- Prefer a previously installed, organization-approved installer in controlled environments instead of allowing
npxto retrieve executable code on demand. - Use lockfiles, registry allowlists, package provenance verification, and restricted installation environments in automated deployments.
- Avoid running the installation command with elevated privileges and minimize credentials exposed to the installation process.
- Pin the installer to an explicitly reviewed version: