Systemd Timer Created

Last updated 6 months ago on 2025-02-03
Created 2 years ago on 2023-02-24

About

Detects the creation of a systemd timer within any of the default systemd timer directories. Systemd timers can be used by an attacker to gain persistence, by scheduling the execution of a command or script. Similarly to cron/at, systemd timers can be set up to execute on boot time, or on a specific point in time, which allows attackers to regain access in case the connection to the infected asset was lost.
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 file.path : (
  "/etc/systemd/system/*", "/etc/systemd/user/*", "/usr/local/lib/systemd/system/*",
  "/lib/systemd/system/*", "/usr/lib/systemd/system/*", "/usr/lib/systemd/user/*",
  "/home/*/.config/systemd/user/*", "/home/*/.local/share/systemd/user/*",
  "/root/.config/systemd/user/*", "/root/.local/share/systemd/user/*"
) and file.extension == "timer" 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/bin/crio", "/usr/sbin/crond",
    "/opt/puppetlabs/puppet/bin/ruby", "/usr/libexec/platform-python", "/kaniko/kaniko-executor",
    "/usr/local/bin/dockerd", "/usr/bin/podman", "/bin/install", "/proc/self/exe", "/kaniko/executor"
  ) or
  process.name like (
    "python*", "crio", "apt-get", "install", "snapd", "cloudflared", "sshd", "convert-usrmerge", "docker-init",
    "google_metadata_script_runner", "ssm-agent-worker", "pacman", "convert2rhel", "platform-python"
  ) 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 == "sed" and file.name : "sed*") or
  (process.name == "perl" and file.name : "e2scrub_all.tmp*") 
)

Install detection rules in Elastic Security

Detect Systemd Timer Created 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).