Elastic Security Detection Rules

Potential Machine Account Relay Attack via SMB

Last updated 8 days ago on 2025-06-16
Created 8 days ago on 2025-06-16

About

Identifies potential relay attacks against a machine account by identifying network share access events coming from a remote source.ip but using the target server computer account. This may indicate a successful SMB relay attack.
Tags
Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: Credential AccessData Source: Elastic DefendData Source: Active DirectoryUse Case: Active Directory MonitoringData Source: Windows Security Event LogsLanguage: eql
Severity
high
Risk Score
73
MITRE ATT&CK™

Credential Access (TA0006)(opens in a new tab or window)

↳ Forced Authentication (T1187)(opens in a new tab or window)

↳ Adversary-in-the-Middle (T1557)(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-system.security*logs-windows.forwarded*winlogbeat-*
Related Integrations

system(opens in a new tab or window)

windows(opens in a new tab or window)

Query
file where event.code == "5145" and endswith(user.name, "$") and

 /* compare computername with user.name and make sure they match */
 startswith~(winlog.computer_name, substring(user.name, 0, -1)) and

 /* exclude local access */
 not endswith(string(source.ip), string(host.ip)) and
 source.ip != "::" and source.ip != null and source.ip != "::1" and source.ip != "127.0.0.1"

Install detection rules in Elastic Security

Detect Potential Machine Account Relay Attack via SMB 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).