T03 · Remote Payload Retrieval and Execution
Error
- Location
- SKILL.md:14
- Finding
- Remote Installer Downloaded and Executed Without Integrity Verification## Vulnerability Details **File Location**: `SKILL.md:14` **Vulnerability Type**: Remote payload retrieval and execution **Risk Level**: High **Complete Code Snippet**: ```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 mutable external content whose exact version, checksum, and signature are not specified by the Skill. Although the documented URL uses HTTPS and belongs to the official `uv` domain, transport encryption alone does not guarantee that the returned script remains identical to the version reviewed. This execution method prevents meaningful inspection before execution and makes the effective payload dependent on the remote server at installation time. Compromise of the hosting service, domain, release infrastructure, or maintainer account could replace the installer with attacker-controlled shell commands. Installing `uv` is ancillary setup rather than core flight-search functionality. Automatically executing a remote installer with all privileges of the invoking user therefore exceeds the minimum access needed merely to document or perform a flight search. ### Attack Path 1. A user follows the prerequisite instructions in `SKILL.md`. 2. `curl` requests the current content of `https://astral.sh/uv/install.sh`. 3. The response is streamed directly to `sh` without version pinning, checksum verification, signature validation, or prior inspection. 4. If the remote response has been maliciously modified, arbitrary shell commands execute with the user's current privileges. 5. The payload can access or modify any files, credentials, processes, and configuration available to that user. ### Impact Assessment Successful exploitation provides arbitrary code execution under the account running the command. A malicious installer could read user-accessible credentials, alter shell configurati ...[truncated 396 chars]
- Remediation
- ## Remediation Suggestions - Remove the `curl | sh` installation pattern. - Prefer installation through a trusted operating-system package manager with package-signing verification. - If a standalone release is required, pin a specific `uv` version and link to its immutable release artifact. - Download the artifact separately, verify a publisher-provided cryptographic signature or pinned SHA-256 checksum, and only then execute it. - Display the downloaded script for review before execution rather than streaming it directly into a shell. - Document that installation must occur as an unprivileged user and must not require `sudo`. - Record the verified version and checksum in the Skill so future audits can evaluate the exact installer being used.
