T03 · Remote Payload Retrieval and Execution
- Location
references/deployment-guides.md:59- Finding
Unverified Remote Installer Executed Directly by a Shell
- Content
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Vulnerability Details
File Location:
references/deployment-guides.md, line 59
Vulnerability Type: Remote payload retrieval and execution
Risk Level: Criticalbash curl -L https://fly.io/install.sh | shTechnical Analysis
The command streams mutable content from an external endpoint directly into
sh. It follows redirects and provides no version pinning, cryptographic checksum verification, signature validation, or opportunity to inspect the downloaded script before execution.Installing the Fly.io CLI supports the Skill's stated deployment functionality, but executing an unverified remote script is not the minimum capability necessary to perform that task. The effective payload can change after the Skill has been reviewed. Compromise of the hosting endpoint, redirect chain, DNS or TLS trust path, or upstream publishing process would allow attacker-controlled shell commands to run with the invoking user's privileges.
Attack Path
- A user requests assistance deploying an application through Fly.io.
- The agent follows the referenced deployment guide and recommends or executes the installation command.
curlretrieves the current content from the remote endpoint and follows any redirects.- The downloaded content is passed directly to
shwithout verification. - If the remote content or delivery path has been compromised, attacker-supplied commands execute immediately.
- Those commands can access files, credentials, environment variables, and services available to the invoking account.
Impact Assessment
Successful exploitation provides arbitrary command execution with the privileges of the user running the command. Depending on that account's access, an attacker could steal deployment credentials, cloud tokens, SSH keys, source code, and environment secrets; alter local files; tamper with deployment artifacts; or establish persistence. The immediate scope is the invoking acco ...[truncated 61 chars]
- Remediation
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Remediation Suggestions
- Do not pipe network responses directly into a command interpreter.
- Prefer an official package manager or a version-pinned release artifact from a verified publisher.
- Download the artifact to a local file as a separate step.
- Verify a publisher-provided cryptographic checksum and, where available, a release signature.
- Inspect the installer before executing it.
- Run installation with an unprivileged account and avoid
sudounless a specific filesystem operation requires it. - Pin the documented CLI version so future remote changes do not silently alter the reviewed installation process.
