T09 · Insecure Skill Coding Practices
Error
- Location
- SKILL.md:82
- Finding
- Shell Command Injection Through Unsafely Interpolated User Input## Vulnerability Details **File Location**: `SKILL.md`, lines 82-85, 94-97, 115-118, and 124-127 **Vulnerability Type**: Shell command injection caused by embedding user-controlled values in shell command templates **Risk Level**: High ### Vulnerable Code ```bash exec curl -s -X POST https://moltiguild-api.onrender.com/api/claim-starter \ -H "Content-Type: application/json" \ -d '{"userId": "USER_ID"}' ``` ```bash exec curl -s -X POST https://moltiguild-api.onrender.com/api/smart-create \ -H "Content-Type: application/json" \ -d '{"task": "DESCRIBE THE TASK", "budget": "0.001", "userId": "USER_ID"}' ``` ```bash exec curl -s -X POST https://moltiguild-api.onrender.com/api/mission/MISSION_ID/rate \ -H "Content-Type: application/json" \ -d '{"rating": RATING_1_TO_5, "userId": "USER_ID", "feedback": "OPTIONAL_FEEDBACK"}' ``` ```bash exec curl -s -X POST https://moltiguild-api.onrender.com/api/create-pipeline \ -H "Content-Type: application/json" \ -d '{"guildId": 1, "task": "TASK", "budget": "0.005", "steps": [{"role": "writer"}, {"role": "reviewer"}], "userId": "USER_ID"}' ``` ### Technical Analysis The skill mandates execution of `curl` through a shell while placing user-controlled task descriptions, feedback, mission identifiers, and user identifiers directly inside command templates. It does not require structured JSON serialization, shell-safe argument passing, or input validation. The JSON request bodies are enclosed in single quotes. If an implementation replaces the documented placeholders directly, an input containing a single quote can terminate the quoted request body. Shell metacharacters following that quote may then be interpreted as additional commands rather than request data. For example, a malicious task or feedback value shaped like `' ; attacker_command ; #` can break out of the intended JSON argument. JSON escaping alone is insufficient because shell parsing occurs ...[truncated 2130 chars]
- Remediation
- ## Remediation Suggestions 1. Replace shell-executed `curl` commands with a structured HTTP tool or language HTTP client that accepts the URL, headers, and body as separate typed arguments. 2. Serialize request bodies with a JSON library rather than manually assembling JSON strings. 3. If shell execution is unavoidable, construct JSON with a safe serializer such as: ```bash payload="$(jq -n \ --arg task "$TASK" \ --arg budget "$BUDGET" \ --arg userId "$USER_ID" \ '{task: $task, budget: $budget, userId: $userId}')" curl -sS -X POST 'https://moltiguild-api.onrender.com/api/smart-create' \ -H 'Content-Type: application/json' \ --data-binary "$payload" ``` 4. Pass commands as an argument array without invoking a shell whenever the execution environment supports that option. 5. Do not use `eval`, nested command construction, or direct placeholder replacement in shell source. 6. Validate constrained fields before transmission: - Require ratings to be integers from 1 through 5. - Require budgets to match the permitted numeric format and range. - Restrict mission, pipeline, and guild identifiers to their documented formats. - Apply reasonable length limits to user IDs, tasks, and feedback. 7. Add explicit instructions warning implementers that task descriptions and feedback are untrusted data and must never be interpolated into shell commands. 8. Inform users that task descriptions, identifiers, and feedback are transmitted to an external service and should not contain credentials, private keys, confidential file contents, or other secrets. 9. Run the skill with least privilege, a minimal environment, restricted filesystem access, and outbound network access limited to the documented API hosts to reduce impact if command handling fails.