diff --git a/Dockerfile b/Dockerfile
index 0002934..36c076a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,13 +1,13 @@
-FROM alpine:3.22.2 as base
+FROM alpine:3.22.2@sha256:4b7ce07002c69e8f3d704a9c5d6fd3053be500b7f1c69fc0d80990c2ad8dd412 AS base
 
-RUN apk update && apk add --no-cache --upgrade rsync openssh-client openssl busybox
+RUN apk update && apk add --no-cache rsync openssh openssl busybox
 
 RUN rm -rf /var/cache/apk/*
 
 COPY docker-rsync/* /bin/
 RUN chmod +x /bin/agent-*
 
-FROM base as build
+FROM base AS build
 
 COPY entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh