Potential Reverse Shell via Background Process

Last updated 5 months ago on 2025-03-20

Created 2 years ago on 2023-09-20

About

Monitors for the execution of background processes with process arguments capable of opening a socket in the /dev/tcp channel. This may indicate the creation of a backdoor reverse connection, and should be investigated further.

Tags

Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: ExecutionData Source: Elastic DefendData Source: Elastic EndgameData Source: CrowdstrikeData Source: SentinelOneLanguage: 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

endgame-*logs-crowdstrike.fdr*logs-endpoint.events.process*logs-sentinel_one_cloud_funnel.*

Related Integrations

endpoint(opens in a new tab or window)

crowdstrike(opens in a new tab or window)

sentinel_one_cloud_funnel(opens in a new tab or window)

Query

process where host.os.type == "linux" and event.type == "start" and
  event.action in ("exec", "exec_event", "start", "ProcessRollup2") and
  process.name in ("setsid", "nohup") and process.args : "*/dev/tcp/*0>&1*" and
  process.parent.name in ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish")

Install detection rules in Elastic Security

Detect Potential Reverse Shell via Background Process 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).