T03 · Remote Payload Retrieval and Execution
Error
- Location
- SKILL.md:141
- Finding
- Unverified Remote Installer Executed Through a Shell Pipeline<![CDATA[ ## Vulnerability Details **File Location**: `SKILL.md`, line 141 **Vulnerability Type**: Remote payload retrieval and execution **Risk Level**: High ### Vulnerable Code ```bash curl -LsSf https://astral.sh/uv/install.sh | sh ``` ### Technical Analysis The installation instruction streams a remotely hosted script directly into `sh`. The script is not pinned to a specific immutable version, saved for inspection, or validated using a cryptographic checksum or signature before execution. HTTPS protects the script while in transit but does not ensure that the content hosted at the URL remains safe or unchanged. Compromise of the remote hosting environment, publication process, DNS/TLS trust chain, or installer account could cause arbitrary attacker-controlled shell commands to be executed. Installing `uv` is relevant to the documented inference workflows, but executing a mutable remote script is not the minimum capability necessary. The Skill metadata already declares `uv` as a prerequisite, so installation can be handled separately through a verified distribution channel. ### Attack Path 1. An attacker compromises the remote installer host, its release process, or another component of the delivery chain. 2. The attacker replaces or modifies `install.sh` with malicious shell commands. 3. A user follows the documented installation instruction. 4. `curl` retrieves the modified script and streams it directly to `sh`. 5. The malicious commands execute with the privileges of the user running the command. 6. The payload can access or modify resources available to that user and may install additional components. ### Impact Assessment Successful exploitation permits arbitrary command execution under the invoking user's account. This may allow access to user-readable documents, source code, model files, credentials, shell configuration, and other local data. It may also permit modification of user-owned files or installation of user-level persistence. Th ...[truncated 267 chars]
- Remediation
- <![CDATA[ ## Remediation Suggestions 1. Remove the direct `curl | sh` pipeline from the Skill. 2. Treat `uv` strictly as a prerequisite and direct users to an independently verified installation process. 3. Prefer a trusted operating-system package manager or an official, version-pinned release artifact. 4. If manual installation is required: - Download a specific release to a local file. - Verify its cryptographic checksum or signature against a value obtained through an independent trusted channel. - Allow the user to inspect the downloaded content. - Execute it only after verification. 5. Pin the installer or binary to an explicit version rather than retrieving mutable content from a generic installation URL. 6. Document that installation should occur without elevated privileges unless elevation is demonstrably necessary. ]]>
