T08 · Insecure Dependencies
Warning
- Location
- SKILL.md:76
- Finding
- Unpinned External Package Execution During Installation## Vulnerability Details **File Location**: `SKILL.md:76` **Vulnerability Type**: Unpinned third-party package execution **Risk Level**: Medium ```bash npx skills add zhaoxinghua09-cell/agent-skills -g ``` ### Technical Analysis The documented installation command invokes `npx` without specifying an exact version or integrity digest for the `skills` package. Depending on the local environment, `npx` may download and execute the currently published package from an external registry. Consequently, the code executed during installation is mutable and falls outside the reviewed project artifact. If the package, publisher account, registry resolution process, or a transitive dependency is compromised, the installation command may execute code different from the code that was originally reviewed. ### Attack Path 1. An attacker compromises the package publisher, package registry entry, or a dependency used by the unpinned `skills` package. 2. The attacker publishes a malicious version under the package name resolved by `npx`. 3. A user follows the installation command in `SKILL.md`. 4. `npx` downloads and executes the malicious or unexpected package version. 5. The package executes with the privileges of the invoking user and performs arbitrary actions permitted to that account. ### Impact Assessment Successful exploitation could provide arbitrary code execution with the installing user's privileges. The attacker could access user-readable files, modify user-owned configuration, steal credentials available to the process, or install modified Skill content. The `-g` option also increases the scope of package installation by requesting a global Skill installation, although it does not itself prove operating-system privilege escalation.
- Remediation
- ## Remediation Suggestions - Pin the installer package to a reviewed, exact version rather than resolving the latest available release. - Where supported, verify the downloaded package with an integrity hash or signed provenance record. - Document the expected package registry and publisher identity. - Avoid global installation unless it is necessary for the Skill's operation. - Prefer a reviewed local installation mechanism that does not execute mutable remote package code. - If the installer must already exist locally, use a mode equivalent to `npx --no-install` to prevent implicit downloads. - Review and lock all transitive dependencies used by the installer.
