diff --git a/Dockerfile b/Dockerfile
index 96851a7f..33dcc7a1 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,5 @@
 #############      builder                                  #############
-FROM eu.gcr.io/gardener-project/3rd/golang:1.15.5 AS builder
+FROM eu.gcr.io/gardener-project/3rd/golang:1.15.5@sha256:5e9360b0462b3717384bbb4330bc75b53dc9c11dabdf39c5834fe8708439f6d2 AS builder
 
 WORKDIR /go/src/github.com/gardener/machine-controller-manager
 COPY . .
@@ -7,7 +7,7 @@ COPY . .
 RUN .ci/build
 
 #############      base                                     #############
-FROM eu.gcr.io/gardener-project/3rd/alpine:3.12.1 as base
+FROM eu.gcr.io/gardener-project/3rd/alpine:3.12.1@sha256:d7342993700f8cd7aba8496c2d0e57be0666e80b4c441925fc6f9361fa81d10e as base
 
 RUN apk add --update bash curl tzdata
 WORKDIR /