T03 · Remote Payload Retrieval and Execution
Error
- Location
- SKILL.md:140
- Finding
- Unverified Remote PowerShell Script Download and Execution## Vulnerability Details **File Location**: `SKILL.md`, lines 140-146 **Vulnerability Type**: Remote payload retrieval and execution **Risk Level**: High **Vulnerable Code**: ```powershell Set-ExecutionPolicy Bypass -Scope Process -Force [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072 iex ((New-Object System.Net.WebClient).DownloadString('https://community.chocolatey.org/install.ps1')) ``` ### Technical Analysis The documented Chocolatey installation workflow downloads a PowerShell script from an external URL and passes its contents directly to `iex` (`Invoke-Expression`). The downloaded payload is therefore executed immediately without first being saved for inspection, pinned to a reviewed version, checked against a trusted cryptographic digest, or validated through an Authenticode signature. The preceding `Set-ExecutionPolicy Bypass -Scope Process -Force` command removes execution-policy restrictions for the current PowerShell process. Although HTTPS protects the connection in transit under normal conditions, it does not make the retrieved content immutable or ensure that it matches the code reviewed during this audit. The effective payload can change whenever the remote script changes. Exploitation would require malicious control or compromise of the remote content delivery path, such as compromise of the upstream origin, its publishing process, or a relevant TLS trust boundary. An attacker able to alter the returned script could place arbitrary PowerShell instructions in the response, which `iex` would then execute in the current security context. ### Attack Path 1. A user requests installation of Chocolatey, a Windows package-management environment, or software for which the skill selects Chocolatey. 2. The workflow determines that Chocolatey is missing and instructs the user to launch the installation flow, potentially from an elevated PowerShell sessi ...[truncated 1249 chars]
- Remediation
- ## Remediation Suggestions Replace the download-and-`iex` pattern with a verifiable, reviewable installation process: 1. Download the installer script or version-pinned Chocolatey package to a local file rather than executing an in-memory response. 2. Pin the artifact to a specific reviewed release and an official, immutable distribution location where available. 3. Obtain the expected SHA-256 digest through a separate trusted channel and compare it with the downloaded file before execution. 4. Validate the file's Authenticode signature and require an expected trusted publisher when an officially signed artifact is available. 5. Stop installation if the hash, signature, publisher, or expected version does not match. 6. Show the artifact source and verification results to the user and require explicit approval before execution. 7. Avoid changing PowerShell execution policy unless strictly necessary. If a process-scoped change is unavoidable, explain its effect and ensure that installation terminates safely on any verification failure. 8. Run installation with the least privileges possible and request elevation only for operations that genuinely require administrative rights. 9. Prefer a trusted, locally available Windows package-management mechanism for installing Chocolatey when such a mechanism supports authenticated and versioned artifacts.