T03 · Remote Payload Retrieval and Execution
Warning
- Location
- SKILL.md:79
- Finding
- Mutable Third-Party JavaScript Is Executed Without Version or Integrity Pinning<![CDATA[ ## Vulnerability Details **File Location**: `SKILL.md:79` and `references/integration.md:27` **Vulnerability Type**: Remote supply-chain payload execution **Risk Level**: Medium ### Vulnerable Code `SKILL.md:79`: ```html <script src="https://www.kivicube.com/lib/iframe-plugin.js"></script> ``` `references/integration.md:27`: ```html <script src="https://www.kivicube.com/lib/iframe-plugin.js"></script> ``` ### Technical Analysis The recommended integration loads executable JavaScript from a mutable external URL. The URL does not identify an immutable release, and the example provides neither a Subresource Integrity hash nor another mechanism for verifying the downloaded file. Although the script is hosted on the declared Kivicube vendor domain and its use is consistent with the Skill's documented purpose, its effective payload can change after this Skill has been reviewed. A compromise of the vendor infrastructure, CDN, DNS resolution path, or deployment account could therefore turn an otherwise legitimate integration into a remote code-execution channel in every host page following this guidance. Unlike iframe content, an external `<script>` executes in the security context of the embedding host page. It can consequently interact with the host DOM, access data available to page JavaScript, make authenticated same-origin requests, and initiate arbitrary outbound requests subject to browser controls and the host's Content Security Policy. ### Attack Path 1. A user generates or implements a host page using the documented script element. 2. An attacker compromises the vendor's script publication infrastructure, CDN, deployment credentials, or another component capable of modifying the resource returned by the URL. 3. The attacker replaces `iframe-plugin.js` with modified JavaScript while retaining the expected URL. 4. A visitor loads the integrating host page. 5. The browser downloads and executes the modified script in the host page's origin ...[truncated 1056 chars]
- Remediation
- <![CDATA[ ## Remediation Suggestions 1. Prefer an immutable, explicitly versioned vendor URL instead of a moving path such as `/lib/iframe-plugin.js`. 2. Obtain a documented cryptographic digest from the vendor and use Subresource Integrity where the delivery configuration supports it: ```html <script src="https://www.kivicube.com/lib/iframe-plugin.VERSION.js" integrity="sha384-REVIEWED_DIGEST" crossorigin="anonymous" ></script> ``` 3. Do not invent or reuse an integrity value. Generate and verify it against a reviewed, approved release. 4. If immutable vendor releases and SRI are unavailable, consider self-hosting an approved copy when licensing and support requirements permit. 5. Pin the approved file checksum in the deployment pipeline and fail builds when the downloaded artifact differs. 6. Apply a restrictive Content Security Policy, limiting `script-src`, `connect-src`, `frame-src`, and other relevant directives to required origins. 7. Monitor vendor security advisories and establish a controlled process for reviewing and updating the pinned plugin version. 8. Apply the hardened loading instructions consistently in both `SKILL.md` and `references/integration.md`. ]]>