diff --git a/build_vbox.sh b/build_vbox.sh
index 79b6c1b..01fa9a0 100755
--- a/build_vbox.sh
+++ b/build_vbox.sh
@@ -1,5 +1,42 @@
 #!/usr/bin/env bash
+
+GOT_PACKER=$(which packer > /dev/null 2>&1; echo $?)
+if [[ "$GOT_PACKER" == "0" ]]; then
+  echo "Packer detected, version: $(packer -v)"
+  PACKER_RUN=$(which packer)
+else
+  echo "No packer binary detected, please make sure you installed it from: https://www.packer.io/downloads.html"
+  exit 1
+fi
+
+# SHAsums to be computed
+SHA_SUMS="1 256 384 512"
+
+checkInstaller () {
+  for sum in $(echo ${SHA_SUMS}); do
+    /usr/bin/wget -q -O scripts/INSTALL.sh.sha${sum} https://raw.githubusercontent.com/MISP/MISP/2.4/INSTALL/INSTALL.sh.sha${sum}
+    INSTsum=$(shasum -a ${sum} scripts/INSTALL.sh | cut -f1 -d\ )
+    chsum=$(cat scripts/INSTALL.sh.sha${sum} | cut -f1 -d\ )
+
+    if [[ "$chsum" == "$INSTsum" ]]; then
+      echo "sha${sum} matches"
+    else
+      echo "sha${sum}: ${chsum} does not match the installer sum of: ${INSTsum}"
+      echo "Deleting installer, please run again."
+      rm scripts/INSTALL.sh
+      exit 1
+    fi
+  done
+}
+
+# Fetch and check installer
+if [[ -f "scripts/INSTALL.sh" ]]; then
+  echo "Checking checksums"
+  checkInstaller
+else
+  /usr/bin/wget -q -O scripts/INSTALL.sh https://raw.githubusercontent.com/MISP/MISP/2.4/INSTALL/INSTALL.sh
+  checkInstaller
+fi
 # Fetching latest MISP LICENSE
-[[ ! -f /script/INSTALL.sh ]] && wget -q -O scripts/INSTALL.sh https://raw.githubusercontent.com/MISP/MISP/2.4/INSTALL/INSTALL.sh
 [[ ! -f /tmp/LICENSE-misp ]] && wget -q -O /tmp/LICENSE-misp https://raw.githubusercontent.com/MISP/MISP/2.4/LICENSE
 packer build -only=virtualbox-iso misp.json