T09 · Insecure Skill Coding Practices
Error
- Location
- scripts/transcribe.sh:4
- Finding
- Attacker-Controlled Destination Can Receive the Bearer Token and Audio Data## Vulnerability Details **File Location**: `scripts/transcribe.sh`, lines 4–10 and 34–39 **Vulnerability Type**: Unvalidated destination URL causing credential and data disclosure **Risk Level**: High ### Vulnerable Code ```bash if [[ $# -lt 1 ]]; then echo "Usage: $0 <audio-file> [url]" exit 1 fi FILE="$1" URL="${2:-https://lotfi-whisper-worker.medtouradmin.workers.dev/transcribe}" ``` ```bash curl -sS -X POST "$URL" \ -H "content-type: $ctype" \ -H "authorization: Bearer $WHISPER_WORKER_TOKEN" \ --data-binary "@$FILE" \ | jq -r '.result.text // .text // .result.response // empty' ``` ### Technical Analysis The script accepts an optional second command-line argument and uses it directly as the destination supplied to `curl`. It does not restrict the URL scheme or validate the destination hostname against the documented Cloudflare Worker. Every request includes the `WHISPER_WORKER_TOKEN` bearer credential and the complete contents of the selected audio file. Consequently, anyone able to influence the script invocation can redirect both assets to an arbitrary server. A non-HTTPS URL can additionally expose them to network interception. This is not shell command injection because `"$URL"` is quoted. The vulnerability is instead an unsafe trust-boundary decision: attacker-controlled input determines which origin receives sensitive authentication and user data. ### Attack Path 1. An attacker persuades a user or agent to invoke the script with an attacker-controlled URL as its second argument. 2. The user has a valid `WHISPER_WORKER_TOKEN` in the environment and selects an audio file for transcription. 3. The script assigns the supplied URL to `URL` without scheme or hostname validation. 4. `curl` sends the bearer token in the `Authorization` header and uploads the complete audio file to that destination. 5. The attacker records the credential and audio data. 6. The attacker may re ...[truncated 779 chars]
- Remediation
- ## Remediation Suggestions 1. Remove the optional URL argument and hardcode the documented endpoint: ```bash URL="https://lotfi-whisper-worker.medtouradmin.workers.dev/transcribe" ``` 2. If endpoint overrides are operationally necessary, require HTTPS and enforce an exact hostname and path allowlist before attaching credentials. 3. Reject URLs containing alternate schemes, unexpected ports, embedded credentials, redirects to untrusted origins, or non-allowlisted hosts. 4. Configure `curl` to use HTTPS-only protocols and fail on HTTP errors: ```bash curl --proto '=https' --fail-with-body --silent --show-error ... ``` 5. Avoid forwarding authorization headers across redirects. Prefer disabling redirects; if redirects are required, validate the final destination and ensure credentials are never sent to another origin. 6. Rotate any token suspected of having been used with an untrusted URL and apply least-privilege scope, expiration, and usage limits to future tokens. 7. Clearly notify users that transcription uploads the selected audio to an external service.