T03 · Remote Payload Retrieval and Execution
Error
- Location
- references/flyio_config.md:20
- Finding
- Unverified Remote Installer Is Piped Directly into a Shell<![CDATA[ ## Vulnerability Details **File Location**: `references/flyio_config.md:20-21` **Vulnerability Type**: Remote payload retrieval and execution **Risk Level**: Critical ### Vulnerable Code ```bash # 1. Install flyctl curl -L https://fly.io/install.sh | sh ``` ### Technical Analysis The installation instructions download mutable content from an external URL and immediately execute it with the current user's shell. There is no version pinning, checksum verification, signature validation, or opportunity to inspect the downloaded script before execution. The URL belongs to Fly.io's official HTTPS domain, which reduces but does not eliminate the risk. Compromise of the remote distribution service, its deployment pipeline, DNS or TLS trust infrastructure, or the installer itself would allow the delivered payload to change after this Skill has been reviewed. This behavior grants remote content all permissions held by the user running the command and exceeds the minimum privilege necessary to document how to install the Fly.io CLI. ### Attack Path 1. An attacker compromises or modifies the remote installer or its delivery infrastructure. 2. A user follows the Skill's quick-start instructions. 3. `curl` retrieves the attacker-controlled version of `install.sh`. 4. The pipe passes the response directly to `sh` without validation. 5. The payload executes with the user's privileges and can access local files, credentials, environment variables, and network resources. ### Impact Assessment Successful exploitation provides arbitrary command execution with the privileges of the invoking user. Depending on those privileges, an attacker could steal Fly.io or quantum-service credentials, modify source files, install persistence, tamper with deployments, or compromise the host. No evidence establishes that the current Fly.io installer is malicious; the vulnerability is the unverified remote execution mechanism. ]]>
- Remediation
- <![CDATA[ ## Remediation Suggestions - Prefer an official operating-system package manager or a manually downloaded, version-pinned release. - Verify the artifact using a checksum or cryptographic signature published through an independent trusted channel. - Download the installer to a local file and inspect it before execution. - Do not pipe network responses directly into an interpreter. - Document the exact expected Fly.io CLI version and authoritative release source. A safer workflow is: ```bash curl --fail --proto '=https' --tlsv1.2 \ -o fly-install.sh https://fly.io/install.sh # Review the file and verify its published checksum/signature before execution. less fly-install.sh sh fly-install.sh ``` Checksum or signature verification must still be added; separating download from execution alone is not sufficient. ]]>
