diff --git a/docker/debian-bullseye/Dockerfile b/docker/debian-bullseye/Dockerfile
index e179c2e..e59fbc9 100644
--- a/docker/debian-bullseye/Dockerfile
+++ b/docker/debian-bullseye/Dockerfile
@@ -12,16 +12,17 @@ RUN useradd -ms /bin/bash ssldump
 RUN passwd -d ssldump
 RUN printf 'ssldump ALL=(ALL) ALL\n' | tee -a /etc/sudoers
 
+USER ssldump
+
 RUN cd /home/ssldump && \
 	git clone https://github.com/adulau/ssldump.git build
 
 RUN cd /home/ssldump/build && \
 	./autogen.sh && \
-	./configure CC=/usr/bin/clang && \
+	./configure CC=/usr/bin/clang CFLAGS="-D_FORTIFY_SOURCE=2 -fstack-protector-strong -Wformat -Werror=format-security -g" && \
 	make && \
 	sudo make install
 
-USER ssldump
 WORKDIR "/home/ssldump"
 
 CMD ["/bin/bash"]
diff --git a/docker/debian-buster/Dockerfile b/docker/debian-buster/Dockerfile
index 4de60d0..c86ce8a 100644
--- a/docker/debian-buster/Dockerfile
+++ b/docker/debian-buster/Dockerfile
@@ -12,6 +12,8 @@ RUN useradd -ms /bin/bash ssldump
 RUN passwd -d ssldump
 RUN printf 'ssldump ALL=(ALL) ALL\n' | tee -a /etc/sudoers
 
+USER ssldump
+
 RUN cd /home/ssldump && \
 	git clone https://github.com/adulau/ssldump.git build
 
@@ -21,7 +23,6 @@ RUN cd /home/ssldump/build && \
 	make && \
 	sudo make install
 
-USER ssldump
 WORKDIR "/home/ssldump"
 
 CMD ["/bin/bash"]
diff --git a/docker/debian-stretch/Dockerfile b/docker/debian-stretch/Dockerfile
index 8fd5775..3e7ef88 100644
--- a/docker/debian-stretch/Dockerfile
+++ b/docker/debian-stretch/Dockerfile
@@ -12,6 +12,8 @@ RUN useradd -ms /bin/bash ssldump
 RUN passwd -d ssldump
 RUN printf 'ssldump ALL=(ALL) ALL\n' | tee -a /etc/sudoers
 
+USER ssldump
+
 RUN cd /home/ssldump && \
 	git clone https://github.com/adulau/ssldump.git build
 
@@ -21,7 +23,6 @@ RUN cd /home/ssldump/build && \
 	make && \
 	sudo make install
 
-USER ssldump
 WORKDIR "/home/ssldump"
 
 CMD ["/bin/bash"]
diff --git a/docker/ubuntu-bionic/Dockerfile b/docker/ubuntu-bionic/Dockerfile
index 9408a02..7c44668 100644
--- a/docker/ubuntu-bionic/Dockerfile
+++ b/docker/ubuntu-bionic/Dockerfile
@@ -12,6 +12,8 @@ RUN useradd -ms /bin/bash ssldump
 RUN passwd -d ssldump
 RUN printf 'ssldump ALL=(ALL) ALL\n' | tee -a /etc/sudoers
 
+USER ssldump
+
 RUN cd /home/ssldump && \
 	git clone https://github.com/adulau/ssldump.git build
 
@@ -21,7 +23,6 @@ RUN cd /home/ssldump/build && \
 	make && \
 	sudo make install
 
-USER ssldump
 WORKDIR "/home/ssldump"
 
 CMD ["/bin/bash"]
diff --git a/docker/ubuntu-focal/Dockerfile b/docker/ubuntu-focal/Dockerfile
index c4e02ab..04502da 100644
--- a/docker/ubuntu-focal/Dockerfile
+++ b/docker/ubuntu-focal/Dockerfile
@@ -12,6 +12,8 @@ RUN useradd -ms /bin/bash ssldump
 RUN passwd -d ssldump
 RUN printf 'ssldump ALL=(ALL) ALL\n' | tee -a /etc/sudoers
 
+USER ssldump
+
 RUN cd /home/ssldump && \
 	git clone https://github.com/adulau/ssldump.git build
 
@@ -21,7 +23,6 @@ RUN cd /home/ssldump/build && \
 	make && \
 	sudo make install
 
-USER ssldump
 WORKDIR "/home/ssldump"
 
 CMD ["/bin/bash"]
diff --git a/docker/ubuntu-groovy/Dockerfile b/docker/ubuntu-groovy/Dockerfile
index 4d3abf8..57d520a 100644
--- a/docker/ubuntu-groovy/Dockerfile
+++ b/docker/ubuntu-groovy/Dockerfile
@@ -12,6 +12,8 @@ RUN useradd -ms /bin/bash ssldump
 RUN passwd -d ssldump
 RUN printf 'ssldump ALL=(ALL) ALL\n' | tee -a /etc/sudoers
 
+USER ssldump
+
 RUN cd /home/ssldump && \
 	git clone https://github.com/adulau/ssldump.git build
 
@@ -21,7 +23,6 @@ RUN cd /home/ssldump/build && \
 	make && \
 	sudo make install
 
-USER ssldump
 WORKDIR "/home/ssldump"
 
 CMD ["/bin/bash"]