File Transfer or Listener Established via Netcat

Last updated 3 months ago on 2025-10-15

Created 6 years ago on 2020-02-18

About

A netcat process is engaging in network activity on a Linux host. Netcat is often used as a persistence mechanism by exporting a reverse shell or by serving a shell on a listening port. Netcat is also sometimes used for data exfiltration.

Tags

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

Severity

medium

Risk Score

MITRE ATT&CK™

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

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

False Positive Examples

Netcat is a dual-use tool that can be used for benign or malicious activity. Netcat is included in some Linux distributions so its presence is not necessarily suspicious. Some normal use of this program, while uncommon, may originate from scripts, automation tools, and frameworks.

License

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

Definition

Rule Type

Event Correlation Rule

Integration Pack

Prebuilt Security Detection Rules

Index Patterns

auditbeat-*endgame-*logs-auditd_manager.auditd-*logs-crowdstrike.fdr*logs-endpoint.events.process*logs-sentinel_one_cloud_funnel.*

Related Integrations

endpoint(external, opens in a new tab or window)

auditd_manager(external, opens in a new tab or window)

crowdstrike(external, opens in a new tab or window)

sentinel_one_cloud_funnel(external, opens in a new tab or window)

Query

✄𐘗text code block:
✄𐘗process where host.os.type == "linux" and event.type == "start" and
event.action in ("exec", "exec_event", "start", "ProcessRollup2", "executed", "process_started") and
process.name in ("nc","ncat","netcat","netcat.openbsd","netcat.traditional") and
process.args like~ (
  /* bind shell to specific port or listener */
  "-*l*","-*p*",
  /* reverse shell to command-line interpreter used for command execution */
  "-*e*",
  /* file transfer via stdout/pipe */
  ">","<", "|"
)

Install detection rules in Elastic Security

Detect File Transfer or Listener Established via Netcat 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(external, opens in a new tab or window).