T03 · Remote Payload Retrieval and Execution
Error
- Location
- SKILL.md:167
- Finding
- Remote Installer Downloaded and Executed Without Integrity Verification## Vulnerability Details **File Location**: `SKILL.md:167` **Vulnerability Type**: Remote payload retrieval and direct shell execution **Risk Level**: Critical **Vulnerable Code**: ```bash curl -LsSf https://astral.sh/uv/install.sh | sh ``` ### Technical Analysis The troubleshooting instructions pipe the response from an external URL directly into `sh`. The retrieved script is not pinned to an immutable version and is not inspected or verified using a cryptographic checksum or signature before execution. Although the URL appears to be the official installer endpoint for uv, the effective payload is mutable and resides outside this audited project. Consequently, the code that will execute may differ from the code available at audit time. Compromise of the upstream server, publishing process, DNS resolution, certificate infrastructure, or network path could turn this instruction into an arbitrary-code-execution channel. Direct execution also prevents the user from reviewing the downloaded content before it runs. This behavior exceeds the minimum privileges required to explain how to install a prerequisite safely. ### Attack Path 1. An attacker compromises the remote installer endpoint, its deployment process, or another component of the delivery chain. 2. The user or Agent encounters the documented `uvx: command not found` condition. 3. The Agent follows the remediation instruction and executes the `curl | sh` pipeline. 4. `curl` retrieves the attacker-controlled response. 5. The response is immediately interpreted by the local shell without integrity verification or review. 6. The payload performs arbitrary actions with the privileges of the user running the Agent. ### Impact Assessment Successful exploitation provides arbitrary command execution under the invoking user's account. The resulting payload could read or modify user-accessible files, steal source code and credentials, alter shell or Agent configuration, in ...[truncated 380 chars]
- Remediation
- ## Remediation Suggestions 1. Remove the direct `curl | sh` installation instruction. 2. Prefer a trusted operating-system package manager or another installation mechanism that supports version pinning and package-signature validation. 3. If a standalone installer is necessary: - Pin an exact uv release. - Download the artifact to a local file without executing it. - Obtain the expected checksum or signature through a separately authenticated release channel. - Verify the artifact before execution. - Display the exact artifact, version, and intended changes to the user. - Require explicit user approval before running it. 4. Execute installation with ordinary user privileges and never recommend `sudo` unless a separately justified operation requires it. 5. Direct users to the official installation documentation rather than automatically executing mutable remote content.