diff --git a/tests/6_docker_security_operations.sh b/tests/6_docker_security_operations.sh
index 3165986..28d6916 100644
--- a/tests/6_docker_security_operations.sh
+++ b/tests/6_docker_security_operations.sh
@@ -40,7 +40,7 @@ images=$(docker images -q | wc -l | awk '{print $1}')
 active_images=0
 
 for c in $(docker inspect -f "{{.Image}}" $(docker ps -qa)); do
-  if docker images --no-trunc -a | grep $c > /dev/null ; then
+  if docker images --no-trunc -a | grep "$c" > /dev/null ; then
     active_images=$(( active_images += 1 ))
   fi
 done
@@ -61,7 +61,7 @@ fi
 check_6_7="6.7 - Avoid container sprawl"
 total_containers=$(docker info 2>/dev/null | grep "Containers" | awk '{print $2}')
 running_containers=$(docker ps -q | wc -l | awk '{print $1}')
-diff="$(($total_containers - $running_containers))"
+diff="$((total_containers - running_containers))"
 if [ "$diff" -gt 25 ]; then
   warn "$check_6_7"
   warn "     * There are currently a total of $total_containers containers, with only $running_containers of them currently running"