diff --git a/Dockerfile b/Dockerfile
index 61bfa3b..f686010 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:latest as builder
+FROM golang:latest@sha256:672a2286da3ee7a854c3e0a56e0838918d0dbb1c18652992930293312de898a6 as builder
 
 ENV CGO_ENABLED=0
 
@@ -13,7 +13,7 @@
 
 RUN go install gomodules.avm99963.com/hgu-sipsettings-reverter
 
-FROM alpine
+FROM alpine@sha256:51b67269f354137895d43f3b3d810bfacd3945438e94dc5ac55fdac340352f48
 LABEL maintainer "me@avm99963.com"
 
 RUN apk add --no-cache tini