T03 · Remote Payload Retrieval and Execution
Error
- Location
- SKILL.md:24
- Finding
- Unverified Remote Script Downloaded and Executed by Bash<![CDATA[ ## Vulnerability Details **File Location**: `SKILL.md`, lines 24-28 **Vulnerability Type**: Remote payload retrieval and immediate execution **Risk Level**: High ```markdown Using installation script (macOS/Linux/Windows): ``` curl -sSL install.tasksquad.ai | bash ``` ``` ### Technical Analysis The installation instructions pipe a remotely downloaded script directly into Bash. The payload is mutable and is neither pinned to a specific version nor verified with a cryptographic checksum or digital signature. The `-sSL` options also suppress normal curl output and follow redirects, allowing the final script to originate from a redirected location without being visibly reviewed. HTTPS protects the connection in transit but does not guarantee that the server, DNS configuration, deployment pipeline, domain account, or published script remains trustworthy. Because the downloaded installer is not included in the audited project, its behavior and effective permissions cannot be statically inspected. Installing a CLI may be necessary for the declared TaskSquad integration, but immediate execution of unverified remote content exceeds the minimum mechanism necessary to perform that installation. ### Attack Path 1. An attacker compromises `install.tasksquad.ai`, its DNS, hosting account, deployment pipeline, or a redirect destination. 2. The attacker replaces the legitimate installer with a malicious shell script. 3. A user or AI agent follows the documented installation command. 4. Curl downloads the attacker-controlled response and streams it directly to Bash. 5. Bash executes the payload immediately without an inspection or integrity-verification step. 6. The payload acts with the privileges of the invoking account and can download further components, access available credentials, alter files, or establish persistence. ### Impact Assessment Successful exploitation provides arbitrary command execution with the privileges of the user running the command. ...[truncated 599 chars]
- Remediation
- <![CDATA[ ## Remediation Suggestions 1. Remove the `curl | bash` installation method. 2. Publish immutable, versioned release artifacts through a documented official release channel. 3. Pin installation instructions to an exact release version rather than a mutable endpoint. 4. Publish SHA-256 or stronger checksums over a separately authenticated channel. 5. Sign releases and document signature verification using a clearly identified signing key. 6. Require users to download the artifact, verify its checksum and signature, inspect it where appropriate, and only then execute or install it. 7. Document the files, services, network connections, and permissions created by the installer. 8. Ensure installation does not require administrator privileges unless a specific component demonstrably needs them. 9. If a shell installer must remain available, host each version at an immutable URL and provide a safe workflow such as: ```bash curl --fail --proto '=https' --tlsv1.2 -o install-tsq.sh \ 'https://example.invalid/releases/vX.Y.Z/install-tsq.sh' echo '<EXPECTED_SHA256> install-tsq.sh' | sha256sum --check less install-tsq.sh bash install-tsq.sh ``` 10. Treat checksum placeholders as documentation examples only; publish a real version-specific digest before recommending the command. ]]>