Systemd-udevd Rule File Creation

Last updated 7 months ago on 2025-01-24
Created 2 years ago on 2023-10-26

About

Monitors for the creation of rule files that are used by systemd-udevd to manage device nodes and handle kernel device events in the Linux operating system. Systemd-udevd can be exploited for persistence by adversaries by creating malicious udev rules that trigger on specific events, executing arbitrary commands or payloads whenever a certain device is plugged in or recognized by the system.
Tags
Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: PersistenceData Source: Elastic DefendLanguage: eql
Severity
low
Risk Score
21
MITRE ATT&CK™

Persistence (TA0003)(opens in a new tab or window)

License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.file*
Related Integrations

endpoint(opens in a new tab or window)

Query
file where host.os.type == "linux" and event.action in ("rename", "creation") and
process.executable != null and file.extension == "rules" and
file.path : (
  "/lib/udev/*", "/etc/udev/rules.d/*", "/usr/lib/udev/rules.d/*", "/run/udev/rules.d/*", "/usr/local/lib/udev/rules.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", "/usr/libexec/netplan/generate",
    "/lib/systemd/system-generators/netplan", "/lib/systemd/systemd", "/usr/bin/containerd", "/usr/sbin/sshd",
    "/kaniko/executor"
  ) or
  file.Ext.original.extension == "dpkg-new" or
  process.executable : (
    "/nix/store/*", "/var/lib/dpkg/*", "/snap/*", "/dev/fd/*", "/usr/lib/*", "/usr/libexec/*"
  ) or
  process.name in (
    "systemd", "netplan", "apt-get", "vmware-config-tools.pl", "systemd-hwdb", "ssm-agent-worker", "crio", "cloud-init", "convert2rhel" 
  ) 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 Systemd-udevd Rule 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).