sigma-rules/rules/windows/discovery_enumerating_domain_trusts_via_nltest.toml

[metadata]
creation_date = "2022/05/31"
integration = ["endpoint", "windows", "system", "m365_defender", "crowdstrike"]
maturity = "production"
updated_date = "2026/05/04"

[rule]
author = ["Elastic"]
description = """
Identifies the use of nltest.exe for domain trust discovery purposes. Adversaries may use this command-line utility to
enumerate domain trusts and gain insight into trust relationships, as well as the state of Domain Controller (DC)
replication in a Microsoft Windows NT Domain.
"""
false_positives = [
    """
    Domain administrators may use this command-line utility for legitimate information gathering purposes, but it is not
    common for environments with Windows Server 2012 and newer.
    """,
]
from = "now-9m"
index = [
    "endgame-*",
    "logs-crowdstrike.fdr*",
    "logs-endpoint.events.process-*",
    "logs-m365_defender.event-*",
    "logs-system.security*",
    "logs-windows.forwarded*",
    "logs-windows.sysmon_operational-*",
    "winlogbeat-*",
]
language = "eql"
license = "Elastic License v2"
name = "Enumerating Domain Trusts via NLTEST.EXE"
note = """## Triage and analysis

### Investigating Enumerating Domain Trusts via NLTEST.EXE

Active Directory (AD) domain trusts define relationships between domains within a Windows AD environment. In this setup, a "trusting" domain permits users from a "trusted" domain to access resources. These trust relationships can be configurable as one-way, two-way, transitive, or non-transitive, enabling controlled access and resource sharing across domains.

This rule identifies the usage of the `nltest.exe` utility to enumerate domain trusts. Attackers can use this information to enable the next actions in a target environment, such as lateral movement.

#### Possible investigation steps

- Investigate the process execution chain (parent process tree) for unknown processes. Examine their executable files for prevalence, whether they are located in expected locations, and if they are signed with valid digital signatures.
- Identify the user account that performed the action and whether it should perform this kind of action.
- Investigate other alerts associated with the user/host during the past 48 hours.

### False positive analysis

- Discovery activities are not inherently malicious if they occur in isolation and are done within the user business context (e.g., an administrator in this context). As long as the analyst did not identify suspicious activity related to the user or host, such alerts can be dismissed.

### Related rules

- Enumerating Domain Trusts via DSQUERY.EXE - 06a7a03c-c735-47a6-a313-51c354aef6c3

### Response and remediation

- Initiate the incident response process based on the outcome of the triage.
- Isolate the involved hosts to prevent further post-compromise behavior.
- Restrict PowerShell usage outside of IT and engineering business units using GPOs, AppLocker, Intune, or similar software.
- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
- Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the mean time to respond (MTTR).
"""

setup = """## Setup

This rule is designed for data generated by [Elastic Defend](https://www.elastic.co/security/endpoint-security), which provides native endpoint detection and response, along with event enrichments designed to work with our detection rules.

Setup instructions: https://ela.st/install-elastic-defend

### Additional data sources

This rule also supports the following third-party data sources. For setup instructions, refer to the links below:

- [CrowdStrike](https://ela.st/crowdstrike-integration)
- [Microsoft Defender XDR](https://ela.st/m365-defender)
- [Sysmon Event ID 1 - Process Creation](https://ela.st/sysmon-event-1-setup)
- [Windows Process Creation Logs](https://ela.st/audit-process-creation)
"""

references = [
    "https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/cc731935(v=ws.11)",
    "https://redcanary.com/blog/how-one-hospital-thwarted-a-ryuk-ransomware-outbreak/",
]
risk_score = 21
rule_id = "84da2554-e12a-11ec-b896-f661ea17fbcd"
severity = "low"
tags = [
    "Domain: Endpoint",
    "OS: Windows",
    "Use Case: Threat Detection",
    "Tactic: Discovery",
    "Data Source: Elastic Endgame",
    "Resources: Investigation Guide",
    "Data Source: Elastic Defend",
    "Data Source: Windows Security Event Logs",
    "Data Source: Microsoft Defender XDR",
    "Data Source: Crowdstrike",
    "Data Source: Sysmon",
]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where host.os.type == "windows" and event.type == "start" and
    process.name : "nltest.exe" and process.args : (
        "/DCLIST:*", "/DCNAME:*", "/DSGET*",
        "/LSAQUERYFTI:*", "/PARENTDOMAIN",
        "/DOMAIN_TRUSTS", "/BDC_QUERY:*"
        ) and 
not process.parent.name : "PDQInventoryScanner.exe" and
not (
  user.id in ("S-1-5-18", "S-1-5-19", "S-1-5-20") and
  /* Don't apply the user.id exclusion to Sysmon for compatibility */
  not data_stream.dataset : ("windows.sysmon_operational", "windows.sysmon")
)
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1018"
name = "Remote System Discovery"
reference = "https://attack.mitre.org/techniques/T1018/"

[[rule.threat.technique]]
id = "T1482"
name = "Domain Trust Discovery"
reference = "https://attack.mitre.org/techniques/T1482/"


[rule.threat.tactic]
id = "TA0007"
name = "Discovery"
reference = "https://attack.mitre.org/tactics/TA0007/"