T03 · Remote Payload Retrieval and Execution
Error
- Location
- SKILL.md:58
- Finding
- Unverified Remote Installer Executed Directly by a Shell## Vulnerability Details **File Location**: `SKILL.md:58` **Vulnerability Type**: Remote payload retrieval and execution **Risk Level**: High **Vulnerable Code**: ```bash curl -fsSL https://parallel.ai/install.sh | bash ``` ### Technical Analysis The installation instructions pipe content retrieved from a remotely controlled URL directly into `bash`. The effective executable payload is not included in the reviewed project and can change at any time after the Skill has been audited. The command provides no version pinning, cryptographic signature validation, checksum verification, or opportunity to inspect the downloaded script before execution. HTTPS protects the connection in transit but does not guarantee that the server, publisher account, DNS configuration, or release infrastructure has not been compromised. Installing `parallel-cli` supports the Skill's declared functionality, but immediate execution of a mutable remote script is not the minimum-risk method needed to install it. The same document provides a `pipx` alternative, demonstrating that direct remote shell execution is not functionally required. That alternative is also not version-pinned, but it does not use the same direct `curl | bash` execution channel. ### Attack Path 1. An attacker compromises or gains control of `parallel.ai/install.sh`, its hosting infrastructure, publisher account, or an equivalent part of its delivery chain. 2. The attacker modifies the remote installer to include arbitrary shell commands. 3. An Agent or user follows the Skill instructions when `parallel-cli` is unavailable. 4. `curl` retrieves the attacker-controlled content and streams it directly to `bash`. 5. The malicious commands execute immediately with all privileges available to the invoking account. ### Impact Assessment Successful exploitation permits arbitrary command execution under the invoking user's security context. The resulting scope may include reading or ...[truncated 440 chars]
- Remediation
- ## Remediation Suggestions - Remove the `curl | bash` installation command. - Prefer installation from a trusted package registry using an explicitly pinned version, for example a reviewed version of `parallel-web-tools[cli]`. - If a shell installer must be supported, download a versioned artifact to a local file rather than streaming it into a shell. - Verify the downloaded artifact using a publisher signature or a SHA-256 checksum obtained through a separately trusted channel. - Allow the installer contents to be inspected before execution. - Execute installation with the least-privileged account possible and do not request administrative privileges unless a documented installation step strictly requires them. - Pin the `pipx` package version and establish a controlled upgrade process so future dependency changes receive separate review.