Proxy Shell Execution via Busybox

Last updated 3 days ago on 2025-11-24
Created 7 days ago on 2025-11-20

About

Detects the execution of a shell through Busybox. Attackers may use this technique to execute shells while attempting to evade detection.
Tags
Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: Defense EvasionTactic: ExecutionData Source: Elastic DefendLanguage: eql
Severity
low
Risk Score
21
MITRE ATT&CK™

Defense Evasion (TA0005)(opens in a new tab or window)

Execution (TA0002)(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.process*
Related Integrations

endpoint(opens in a new tab or window)

Query
process where host.os.type == "linux" and  event.type == "start" and event.action == "exec" and process.parent.name == "busybox" and
process.name in ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish") and
process.command_line in ("bash", "bash-", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish") and
not (
  process.args == "-c" or
  process.parent.args : (
    "crond", "/usr/sbin/crond", "/local-registrator.sh", "/var/atlassian/application-data/bamboo-agent*"
  ) or
  process.parent.command_line in (
    "sh /readonly-config/fix-split-brain.sh",
    "/bin/sh -c /health-check.sh || bash -c 'kill -s 15 $(pidof siridb-server) && (sleep 10; kill -s 9 $(pidof siridb-server))'"
  ) or
  process.command_line == "bash /etc/kafka/docker/run" or
  process.parent.command_line like (
    "/bin/sh -c apk add*", "/bin/sh -c crm-cron-enabled*", "udhcpc -n -p /run/udhcpc.*", "flock -x*"
  ) or
  process.working_directory == "/usr/share/grafana"
)

Install detection rules in Elastic Security

Detect Proxy Shell Execution via Busybox 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).