Potential Reverse Shell via Suspicious Binary

Last updated 6 months ago on 2025-02-04

Created 2 years ago on 2023-07-05

About

This detection rule detects the creation of a shell through a chain consisting of the execution of a suspicious binary (located in a commonly abused location or executed manually) followed by a network event and ending with a shell being spawned. Stageless reverse tcp shells display this behaviour. Attackers may spawn reverse shells to establish persistence onto a target system.

Tags

Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: ExecutionData Source: Elastic DefendLanguage: eql

Severity

medium

Risk Score

MITRE ATT&CK™

Execution (TA0002)(opens in a new tab or window)

↳ Command and Scripting Interpreter (T1059)(opens in a new tab or window)

Command and Control (TA0011)(opens in a new tab or window)

↳ Application Layer Protocol (T1071)(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.network*logs-endpoint.events.process*
Related Integrations: endpoint(opens in a new tab or window)
Query

sequence by host.id, process.entity_id with maxspan=1s
[ process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and
  process.executable : (
  "./*", "/tmp/*", "/var/tmp/*", "/var/www/*", "/dev/shm/*", "/etc/init.d/*", "/etc/rc*.d/*",
  "/etc/crontab", "/etc/cron.*", "/etc/update-motd.d/*", "/usr/lib/update-notifier/*",
  "/boot/*", "/srv/*", "/run/*", "/root/*", "/etc/rc.local"
   ) and
  process.parent.name : ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish") and not
  process.name : ("curl", "wget", "ping", "apt", "dpkg", "yum", "rpm", "dnf", "dockerd") ]
[ network where host.os.type == "linux" and event.type == "start" and event.action in ("connection_attempted", "connection_accepted") and
  process.executable : (
  "./*", "/tmp/*", "/var/tmp/*", "/var/www/*", "/dev/shm/*", "/etc/init.d/*", "/etc/rc*.d/*",
  "/etc/crontab", "/etc/cron.*", "/etc/update-motd.d/*", "/usr/lib/update-notifier/*",
  "/boot/*", "/srv/*", "/run/*", "/root/*", "/etc/rc.local"
   ) and destination.ip != null and destination.ip != "127.0.0.1" and destination.ip != "::1" ]
[ process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and
  process.name : ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish") and
  process.parent.name : ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish") ]

Install detection rules in Elastic Security

Detect Potential Reverse Shell via Suspicious Binary 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).