Elastic Security Detection Rules

Successful SSH Authentication from Unusual SSH Public Key

Last updated 10 days ago on 2025-02-21
Created 10 days ago on 2025-02-21

About

This rule leverages the new_terms rule type to detect successful SSH authentications via a public key that has not been seen in the last 10 days. Public key authentication is a secure method for authenticating users to a server. Monitoring unusual public key authentication events can help detect unauthorized access attempts or suspicious activity on the system.
Tags
Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: Initial AccessData Source: Elastic DefendLanguage: kuery
Severity
low
Risk Score
21
MITRE ATT&CK™

Initial Access (TA0001)(opens in a new tab or window)

↳ Valid Accounts (T1078)(opens in a new tab or window)

False Positive Examples
This rule may trigger in cases where a user has routine work patterns that result in infrequent authentications.
License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
New Terms Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-system.auth-*filebeat-*
Related Integrations

system(opens in a new tab or window)

Query
event.category:authentication and host.os.type:linux and event.action:ssh_login and event.outcome:success and system.auth.ssh.method:publickey

Install detection rules in Elastic Security

Detect Successful SSH Authentication from Unusual SSH Public Key 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).