diff --git a/cdist/conf/type/__apt_mark/explorer/apt_version b/cdist/conf/type/__apt_mark/explorer/apt_version
index 32a0a58f..827d9db2 100644
--- a/cdist/conf/type/__apt_mark/explorer/apt_version
+++ b/cdist/conf/type/__apt_mark/explorer/apt_version
@@ -26,6 +26,6 @@ apt_version_is=$(dpkg-query --show --showformat '${Version}' apt)
 
 apt_version_should=0.8.14.2
 
-dpkg --compare-versions $apt_version_should le $apt_version_is \
+dpkg --compare-versions "$apt_version_should" le "$apt_version_is" \
     && echo 0 \
     || echo 1
diff --git a/cdist/conf/type/__apt_mark/explorer/package_installed b/cdist/conf/type/__apt_mark/explorer/package_installed
index c78ac3a9..c37c5e76 100644
--- a/cdist/conf/type/__apt_mark/explorer/package_installed
+++ b/cdist/conf/type/__apt_mark/explorer/package_installed
@@ -24,7 +24,7 @@ else
     name="$__object_id"
 fi
 
-dpkg-query --show --showformat '${Status}' $name 2>/dev/null \
+dpkg-query --show --showformat '${Status}' "$name" 2>/dev/null \
     | grep -q 'ok installed' \
     && echo 0 \
     || echo 1
diff --git a/cdist/conf/type/__apt_mark/explorer/state b/cdist/conf/type/__apt_mark/explorer/state
index 3b70003a..565ad70f 100644
--- a/cdist/conf/type/__apt_mark/explorer/state
+++ b/cdist/conf/type/__apt_mark/explorer/state
@@ -24,4 +24,4 @@ else
     name="$__object_id"
 fi
 
-apt-mark showhold | grep -q $name && echo hold || echo unhold
+apt-mark showhold | grep -q "$name" && echo hold || echo unhold