fix: Uploading a file by providing an origin URL allows for Server-Side Request Forgery (SSRF); fixes vulnerability [GHSA-x4qj-2f4q-r4rx](GHSA-x4qj-2f4q-r4rx) (#9904)

Author: mtrezza

spec/ParseFile.spec.js

@@ -633,6 +633,80 @@ describe('Parse.File testing', () => {
         done();
       });
     });
+
+    describe('URI-backed file upload is disabled to prevent SSRF attack', () => {
+      const express = require('express');
+      let testServer;
+      let testServerPort;
+      let requestsMade;
+
+      beforeEach(async () => {
+        requestsMade = [];
+        const app = express();
+        app.use((req, res) => {
+          requestsMade.push({ url: req.url, method: req.method });
+          res.status(200).send('test file content');
+        });
+        testServer = app.listen(0);
+        testServerPort = testServer.address().port;
+      });
+
+      afterEach(async () => {
+        if (testServer) {
+          await new Promise(resolve => testServer.close(resolve));
+        }
+        Parse.Cloud._removeAllHooks();
+      });
+
+      it('does not access URI when file upload attempted over REST', async () => {
+        const response = await request({
+          method: 'POST',
+          url: 'http://localhost:8378/1/classes/TestClass',
+          headers: {
+            'Content-Type': 'application/json',
+            'X-Parse-Application-Id': 'test',
+            'X-Parse-REST-API-Key': 'rest',
+          },
+          body: {
+            file: {
+              __type: 'File',
+              name: 'test.txt',
+              _source: {
+                format: 'uri',
+                uri: `http://127.0.0.1:${testServerPort}/secret-file.txt`,
+              },
+            },
+          },
+        });
+        expect(response.status).toBe(201);
+        // Verify no HTTP request was made to the URI
+        expect(requestsMade.length).toBe(0);
+      });
+
+      it('does not access URI when file created in beforeSave trigger', async () => {
+        Parse.Cloud.beforeSave(Parse.File, () => {
+          return new Parse.File('trigger-file.txt', {
+            uri: `http://127.0.0.1:${testServerPort}/secret-file.txt`,
+          });
+        });
+        await expectAsync(
+          request({
+            method: 'POST',
+            headers: {
+              'Content-Type': 'application/octet-stream',
+              'X-Parse-Application-Id': 'test',
+              'X-Parse-REST-API-Key': 'rest',
+            },
+            url: 'http://localhost:8378/1/files/test.txt',
+            body: 'test content',
+          })
+        ).toBeRejectedWith(jasmine.objectContaining({
+          status: 400
+        }));
+        // Verify no HTTP request was made to the URI
+        expect(requestsMade.length).toBe(0);
+      });
+    });
   });
 
   describe('deleting files', () => {

src/Routers/FilesRouter.js

@@ -5,34 +5,8 @@ import Parse from 'parse/node';
 import Config from '../Config';
 import logger from '../logger';
 const triggers = require('../triggers');
-const http = require('http');
 const Utils = require('../Utils');
 
-const downloadFileFromURI = uri => {
-  return new Promise((res, rej) => {
-    http
-      .get(uri, response => {
-        response.setDefaultEncoding('base64');
-        let body = `data:${response.headers['content-type']};base64,`;
-        response.on('data', data => (body += data));
-        response.on('end', () => res(body));
-      })
-      .on('error', e => {
-        rej(`Error downloading file from ${uri}: ${e.message}`);
-      });
-  });
-};
-
-const addFileDataIfNeeded = async file => {
-  if (file._source.format === 'uri') {
-    const base64 = await downloadFileFromURI(file._source.uri);
-    file._previousSave = file;
-    file._data = base64;
-    file._requestTask = null;
-  }
-  return file;
-};
-
 export class FilesRouter {
   expressRouter({ maxUploadSize = '20Mb' } = {}) {
     var router = express.Router();
@@ -210,8 +184,6 @@ export class FilesRouter {
       }
       // if the file returned by the trigger has already been saved skip saving anything
       if (!saveResult) {
-        // if the ParseFile returned is type uri, download the file before saving it
-        await addFileDataIfNeeded(fileObject.file);
         // update fileSize
         const bufferData = Buffer.from(fileObject.file._data, 'base64');
         fileObject.fileSize = Buffer.byteLength(bufferData);