Openssl Client or Server Activity

Last updated 5 months ago on 2025-03-20
Created a year ago on 2024-07-30

About

This rule identifies when the openssl client or server is used to establish a connection. Attackers may use openssl to establish a secure connection to a remote server or to create a secure server to receive connections. This activity may be used to exfiltrate data or establish a command and control channel.
Tags
Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: ExecutionData Source: Elastic DefendData Source: Elastic EndgameData Source: SentinelOneLanguage: eql
Severity
low
Risk Score
21
MITRE ATT&CK™

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

Command and Control (TA0011)(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-endpoint.events.process*logs-sentinel_one_cloud_funnel.*
Related Integrations

endpoint(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") and
  process.name == "openssl" and (
    (process.args == "s_client" and process.args : ("-connect", "*:*") and not process.args == "-showcerts") or
    (process.args == "s_server" and process.args == "-port")
  ) and
  not process.parent.executable in (
    "/pro/xymon/client/ext/awsXymonCheck.sh", "/opt/antidot-svc/nrpe/plugins/check_cert", "/etc/zabbix/scripts/check_dane_tlsa.sh"
  )

Install detection rules in Elastic Security

Detect Openssl Client or Server Activity 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).