T03 · Remote Payload Retrieval and Execution
Error
- Location
scripts/data_asset_analyzer.py:76- Finding
Mutable Remote Payload Retrieved and Executed at Runtime
- Content
View full analysis
=1.0.0", # ] # /// ``` ```python server_params = StdioServerParameters( command='/root/.local/bin/uvx', args=[ '--from', 'git+https://github.com/volcengine/mcp-server@main#subdirectory=server/mcp_server_bytehouse', 'mcp_bytehouse', '-t', 'stdio' ], env=env ) ``` ### Technical Analysis The analyzer invokes `uvx` with a Git dependency referencing the mutable `main` branch of an external repository. Consequently, the code executed by the Skill can change after this package has been reviewed, without any modification to the local Skill files. The dependency has no immutable commit reference, release tag verification, artifact hash, or signature validation. The script-level `mcp>=1.0.0` declaration is also open-ended, allowing later versions to be selected. The most direct risk, however, is the explicit retrieval and execution of the remote Git payload. Because the fetched MCP server executes as a local subprocess, it runs with the operating-system identity and environment of the user invoking the analyzer. This establishes a remote code-execution channel controlled by the current contents of the external branch. ### Attack Path 1. An attacker compromises the upstream repository, a maintainer account, or another part of its publishing workflow. 2. The attacker introduces malicious code into the referenced `main` branch under the ByteHouse MCP server subdirectory. 3. A user invokes `scripts/data_asset_analyzer.py`. 4. The script runs `uvx --from git+https://github.com/volcengine/mcp-server@main...`. 5. `uvx` retrieves and executes the altered MCP server. 6. The malicious process runs with the invoking user's permissions and receives the ...[truncated 805 chars]- Remediation
View remediation
#subdirectory=server/mcp_server_bytehouse', 'mcp_bytehouse', '-t', 'stdio' ] ``` 2. Prefer a trusted, versioned release artifact over installing directly from a source branch. 3. Verify package hashes or signatures before execution and maintain a lockfile containing exact versions and integrity metadata. 4. Pin the `mcp` dependency to a reviewed exact version rather than using `mcp>=1.0.0`. 5. Perform dependency updates through an explicit review process rather than resolving new code during ordinary Skill execution. 6. Run the MCP server in a sandbox or restricted service account with limited filesystem and network access. ]]>