diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index beacc960ab8871745c596eca61cae9375af3818a..9bc432f03a59798c9649b47f18bc57d9fc9c7d1b 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -24,11 +24,11 @@ build_image:
     - docker tag $CI_REGISTRY_IMAGE:$CI_BUILD_TAG $CI_REGISTRY_IMAGE:latest
     - docker push "$CI_REGISTRY_IMAGE:$CI_BUILD_TAG"
     - docker push "$CI_REGISTRY_IMAGE:latest"
-    - docker login -u DOCKER_HUB_USER -p DOCKER_HUB_PASSWD
+    - docker login -u "$DOCKER_HUB_USER" -p "$DOCKER_HUB_PASSWD"
     - docker tag $CI_REGISTRY_IMAGE:$CI_BUILD_TAG dunitrust/dunitrust-env-build:$CI_BUILD_TAG
-    - docker push dunitrust/dunitrust-env-build:$CI_BUILD_TAG
+    - docker push "dunitrust/dunitrust-env-build:$CI_BUILD_TAG"
     - docker tag $CI_REGISTRY_IMAGE:$CI_BUILD_TAG dunitrust/dunitrust-env-build:latest
-    - docker push dunitrust/dunitrust-env-build:latest
+    - docker push "dunitrust/dunitrust-env-build:latest"
 
   only:
     - tags