diff --git a/.clusterfuzzlite/Dockerfile b/.clusterfuzzlite/Dockerfile
index d6eb48f7..8f1ebd9b 100644
--- a/.clusterfuzzlite/Dockerfile
+++ b/.clusterfuzzlite/Dockerfile
@@ -22,10 +22,11 @@
 
 FROM gcr.io/oss-fuzz-base/base-builder:v1@sha256:92851d384e2525f2b8c63922994610de685438778883987a50a3509f0bf08917
 
-RUN git clone --depth 1 https://github.com/openwall/john.git /upstream
-RUN apt-get update -qq && \
-    apt-get install -y --no-install-recommends libssl-dev=* zlib1g-dev=* && \
-    apt-get install -y --no-install-recommends libgmp-dev=* libpcap-dev=* libbz2-dev=* \
+RUN git clone --depth 1 https://github.com/openwall/john.git /upstream \
+    && apt-get update -qq \
+    && apt-get install -y --no-install-recommends \
+        libbz2-dev=* libgmp-dev=* libpcap-dev=* \
+        libssl-dev=* zlib1g-dev=* \
 # ==================================================================
 # Clean up the image (shrink the Docker image)
 # ------------------------------------------------------------------
@@ -35,4 +36,6 @@ RUN apt-get update -qq && \
 WORKDIR $SRC/john
 COPY .clusterfuzzlite/build.sh $SRC/
 COPY scripts/helper.sh /upstream
+
+USER tester
 HEALTHCHECK NONE
diff --git a/CI/Dockerfiles/Dockerfile.FedoraLatest b/CI/Dockerfiles/Dockerfile.FedoraLatest
index 0359827c..053ea808 100644
--- a/CI/Dockerfiles/Dockerfile.FedoraLatest
+++ b/CI/Dockerfiles/Dockerfile.FedoraLatest
@@ -30,8 +30,10 @@ RUN dnf -y -q update \
         @development-tools openssl-devel gmp-devel libpcap-devel bzip2-devel wget \
         clang libasan libubsan libtsan american-fuzzy-lop zzuf pocl-devel \
         american-fuzzy-lop-clang \
-    && useradd -U -m JtR
+    && useradd -U -m tester
 
-USER JtR
 ENV BASE fedora
-CMD /bin/bash
+CMD [ "/bin/bash" ]
+
+USER tester
+HEALTHCHECK NONE
diff --git a/CI/Dockerfiles/Dockerfile.OpenCL b/CI/Dockerfiles/Dockerfile.OpenCL
index c6b2ae08..4c560490 100644
--- a/CI/Dockerfiles/Dockerfile.OpenCL
+++ b/CI/Dockerfiles/Dockerfile.OpenCL
@@ -27,17 +27,19 @@ LABEL org.opencontainers.image.source="https://github.com/openwall/john-packages
 
 RUN apt-get update -qq \
     && export DEBIAN_FRONTEND="noninteractive" \
-    && apt-get install -y \
-        build-essential libssl-dev yasm libgmp-dev libpcap-dev pkg-config debhelper libnet1-dev \
-        libbz2-dev wget llvm libomp-dev zlib1g-dev git clang afl++ zzuf \
-        libpocl-dev ocl-icd-opencl-dev ocl-icd-libopencl1 pocl-opencl-icd opencl-headers \
-    && useradd -U -m JtR \
+    && apt-get install -y --no-install-recommends \
+        afl++ build-essential clang debhelper git libbz2-dev libgmp-dev libnet1-dev libomp-dev \
+        libpcap-dev libpocl-dev libssl-dev llvm ocl-icd-libopencl1 ocl-icd-opencl-dev \
+        opencl-headers pkg-config pocl-opencl-icd wget yasm zlib1g-dev zzuf \
+    && useradd -U -m tester \
 # ==================================================================
 # Clean up the image (shrink the Docker image)
 # ------------------------------------------------------------------
     && apt-get -y clean \
     && rm -rf /var/lib/apt/lists/* /var/cache/apt/archives/*
 
-# USER JtR => it is much better to use root on Travis
-ENV BASE ubuntu
-CMD /bin/bash
+ENV BASE ubuntu-pocl
+CMD [ "/bin/bash" ]
+
+USER tester
+HEALTHCHECK NONE
diff --git a/CI/Dockerfiles/Dockerfile.OpenCL-IntelCPU b/CI/Dockerfiles/Dockerfile.OpenCL-IntelCPU
index 0785a6c9..d1033210 100644
--- a/CI/Dockerfiles/Dockerfile.OpenCL-IntelCPU
+++ b/CI/Dockerfiles/Dockerfile.OpenCL-IntelCPU
@@ -27,7 +27,7 @@ LABEL org.opencontainers.image.source="https://github.com/openwall/john-packages
 
 # DO NOT update this automatically. OpenCL drivers are fragile and must be maintained very carefully.
 # RUN apt-get update -qq \
-#     && apt-get install -y \
+#     && apt-get install -y --no-install-recommends \
 #         build-essential libssl-dev zlib1g-dev yasm libgmp-dev libpcap-dev \
 #         pkg-config libbz2-dev wget \
 #         ocl-icd-opencl-dev clinfo git \
@@ -38,11 +38,14 @@ LABEL org.opencontainers.image.source="https://github.com/openwall/john-packages
 #     && apt-get update -qq \
 #     && apt-get install -y \
 #         intel-oneapi-runtime-opencl intel-basekit \
-#     && useradd -U -m JtR \
+#     && useradd -U -m tester \
 #     && apt-get -y clean \
 #     && rm -rf /var/lib/apt/lists/* /var/cache/apt/archives/*
 
 # Workaround for an issue in Intel libraries installation script
 ENV LD_LIBRARY_PATH=/opt/intel/oneapi/2024.0/lib/:"$LD_LIBRARY_PATH"
 ENV BASE ubuntu
-CMD /bin/bash
+CMD [ "/bin/bash" ]
+
+USER tester
+HEALTHCHECK NONE
diff --git a/CI/Dockerfiles/Dockerfile.RHUbi8 b/CI/Dockerfiles/Dockerfile.RHUbi8
index cf84abd8..3f5445f3 100644
--- a/CI/Dockerfiles/Dockerfile.RHUbi8
+++ b/CI/Dockerfiles/Dockerfile.RHUbi8
@@ -28,7 +28,11 @@ LABEL org.opencontainers.image.source="https://github.com/openwall/john-packages
 RUN yum -y -q update \
     && yum -y install \
         openssl-devel gmp-devel libpcap-devel bzip2-devel wget gcc git perl \
-    && useradd -U -m JtR
+    && yum clean all \
+    && useradd -U -m tester
 
 ENV BASE RedHat-UBI
-CMD /bin/bash
+CMD [ "/bin/bash" ]
+
+USER tester
+HEALTHCHECK NONE
\ No newline at end of file
diff --git a/CI/Dockerfiles/Dockerfile.UbuntuDevel b/CI/Dockerfiles/Dockerfile.UbuntuDevel
index 92fed6b1..7eab6060 100644
--- a/CI/Dockerfiles/Dockerfile.UbuntuDevel
+++ b/CI/Dockerfiles/Dockerfile.UbuntuDevel
@@ -27,16 +27,18 @@ LABEL org.opencontainers.image.source="https://github.com/openwall/john-packages
 
 RUN apt-get update -qq \
     && export DEBIAN_FRONTEND="noninteractive" \
-    && apt-get install -y \
-        build-essential libssl-dev yasm libgmp-dev libpcap-dev pkg-config debhelper libnet1-dev \
-        libbz2-dev wget llvm libomp-dev zlib1g-dev git clang \
-    && useradd -U -m JtR \
+    && apt-get install -y --no-install-recommends \
+         build-essential clang debhelper git libbz2-dev libgmp-dev libnet1-dev \
+         libomp-dev libpcap-dev libssl-dev llvm pkg-config wget yasm zlib1g-dev \
+    && useradd -U -m tester \
 # ==================================================================
 # Clean up the image (shrink the Docker image)
 # ------------------------------------------------------------------
     && apt-get -y clean \
     && rm -rf /var/lib/apt/lists/* /var/cache/apt/archives/*
 
-# USER JtR => it is much better to use root on Travis
 ENV BASE ubuntu
-CMD /bin/bash
+CMD [ "/bin/bash" ]
+
+USER tester
+HEALTHCHECK NONE
diff --git a/CI/Dockerfiles/Dockerfile.UbuntuRolling b/CI/Dockerfiles/Dockerfile.UbuntuRolling
index 537ae8c3..8a0064a6 100644
--- a/CI/Dockerfiles/Dockerfile.UbuntuRolling
+++ b/CI/Dockerfiles/Dockerfile.UbuntuRolling
@@ -27,17 +27,18 @@ LABEL org.opencontainers.image.source="https://github.com/openwall/john-packages
 
 RUN apt-get update -qq \
     && export DEBIAN_FRONTEND="noninteractive" \
-    && apt-get install -y \
-        build-essential libssl-dev yasm libgmp-dev libpcap-dev pkg-config debhelper libnet1-dev \
-        libbz2-dev wget llvm libomp-dev zlib1g-dev git clang \
-        libusb-1.0-0-dev \
-    && useradd -U -m JtR \
+    && apt-get install -y --no-install-recommends \
+        build-essential clang debhelper git libbz2-dev libgmp-dev libnet1-dev libomp-dev \
+        libpcap-dev libssl-dev libusb-1.0-0-dev llvm pkg-config wget yasm zlib1g-dev \
+    && useradd -U -m tester \
 # ==================================================================
 # Clean up the image (shrink the Docker image)
 # ------------------------------------------------------------------
     && apt-get -y clean \
     && rm -rf /var/lib/apt/lists/* /var/cache/apt/archives/*
 
-# USER JtR => it is much better to use root on Travis
 ENV BASE ubuntu
-CMD /bin/bash
+CMD [ "/bin/bash" ]
+
+USER tester
+HEALTHCHECK NONE
\ No newline at end of file
diff --git a/CI/Dockerfiles/Dockerfile.flatpak.package b/CI/Dockerfiles/Dockerfile.flatpak.package
index c2c4162b..f1490da8 100644
--- a/CI/Dockerfiles/Dockerfile.flatpak.package
+++ b/CI/Dockerfiles/Dockerfile.flatpak.package
@@ -26,12 +26,14 @@ LABEL description="Docker images for John the Ripper CI (1.0.Fedora Latest Flatp
 LABEL org.opencontainers.image.source="https://github.com/openwall/john-packages"
 
 RUN dnf -y -q update \
-    && dnf -y    install \
+    && dnf -y install \
         flatpak flatpak-builder elfutils wget git \
     && flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo \
     && flatpak install -y flathub org.freedesktop.Platform//24.08 org.freedesktop.Sdk//24.08 \
-    && useradd -U -m JtR
+    && useradd -U -m tester
 
-USER JtR
 ENV BASE fedora
-CMD /bin/bash
+CMD [ "/bin/bash" ]
+
+USER tester
+HEALTHCHECK NONE
\ No newline at end of file