file where host.os.type == "linux" and event.action in ("rename", "creation") and
file.path : "/etc/update-motd.d/*" and not (
process.executable in (
"/bin/dpkg", "/usr/bin/dpkg", "/bin/dockerd", "/usr/bin/dockerd", "/usr/sbin/dockerd", "/bin/microdnf",
"/usr/bin/microdnf", "/bin/rpm", "/usr/bin/rpm", "/bin/snapd", "/usr/bin/snapd", "/bin/yum", "/usr/bin/yum",
"/bin/dnf", "/usr/bin/dnf", "/bin/podman", "/usr/bin/podman", "/bin/dnf-automatic", "/usr/bin/dnf-automatic",
"/bin/pacman", "/usr/bin/pacman", "/usr/bin/dpkg-divert", "/bin/dpkg-divert", "/sbin/apk", "/usr/sbin/apk",
"/usr/local/sbin/apk", "/usr/bin/apt", "/usr/sbin/pacman", "/bin/podman", "/usr/bin/podman", "/usr/bin/puppet",
"/bin/puppet", "/opt/puppetlabs/puppet/bin/puppet", "/usr/bin/chef-client", "/bin/chef-client",
"/bin/autossl_check", "/usr/bin/autossl_check", "/proc/self/exe", "/dev/fd/*", "/usr/bin/pamac-daemon",
"/bin/pamac-daemon", "/usr/lib/snapd/snapd", "/usr/local/bin/dockerd"
) or
file.extension in ("swp", "swpx", "swx", "dpkg-remove") or
file.Ext.original.extension == "dpkg-new" or
process.executable : (
"/nix/store/*", "/var/lib/dpkg/*", "/tmp/vmis.*", "/snap/*", "/dev/fd/*", "/usr/lib/virtualbox/*"
) or
process.executable == null or
process.name in ("executor", "dockerd", "crio") or
(process.name == "sed" and file.name : "sed*") or
(process.name == "perl" and file.name : "e2scrub_all.tmp*")
)
Install detection rules in Elastic Security
Detect Message-of-the-Day (MOTD) File Creation in the Elastic Security detection engine by installing this rule into your Elastic Stack.
To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).