sigma-rules/rules/windows/discovery_admin_recon.toml

[metadata]
creation_date = "2020/12/04"
integration = ["endpoint", "windows"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
updated_date = "2023/09/14"

[rule]
author = ["Elastic"]
description = """
Identifies instances of lower privilege accounts enumerating Administrator accounts or groups using built-in Windows
tools.
"""
from = "now-9m"
index = ["logs-endpoint.events.*", "winlogbeat-*", "logs-windows.*", "endgame-*"]
language = "eql"
license = "Elastic License v2"
name = "Enumeration of Administrator Accounts"
note = """## Triage and analysis

### Investigating Enumeration of Administrator Accounts

After successfully compromising an environment, attackers may try to gain situational awareness to plan their next steps. This can happen by running commands to enumerate network resources, users, connections, files, and installed security software.

This rule looks for the execution of the `net` and `wmic` utilities to enumerate administrator-related users or groups in the domain and local machine scope. Attackers can use this information to plan their next steps of the attack, such as mapping targets for credential compromise and other post-exploitation activities.

#### 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.
- Investigate any abnormal account behavior, such as command executions, file creations or modifications, and network connections.

### False positive analysis

- Discovery activities are not inherently malicious if they occur in isolation. As long as the analyst did not identify suspicious activity related to the user or host, such alerts can be dismissed.

### Related rules

- AdFind Command Activity - eda499b8-a073-4e35-9733-22ec71f57f3a

### 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.
- Investigate credential exposure on systems compromised or used by the attacker to ensure all compromised accounts are identified. Reset passwords for these accounts and other potentially compromised credentials, such as email, business systems, and web services.
- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and malware components.
- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
- 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

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
"""
risk_score = 21
rule_id = "871ea072-1b71-4def-b016-6278b505138d"
severity = "low"
tags = ["Domain: Endpoint",
        "OS: Windows",
        "Use Case: Threat Detection",
        "Tactic: Discovery",
        "Resources: Investigation Guide",
        "Data Source: Elastic Endgame",
        "Data Source: Elastic Defend"
        ]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where host.os.type == "windows" and event.type == "start" and
(
  (((process.name : "net.exe" or process.pe.original_file_name == "net.exe") or
    ((process.name : "net1.exe" or process.pe.original_file_name == "net1.exe") and
        not process.parent.name : "net.exe")) and
   process.args : ("group", "user", "localgroup") and
   process.args : ("*admin*", "Domain Admins", "Remote Desktop Users", "Enterprise Admins", "Organization Management") and
   not process.args : "/add")

   or

  ((process.name : "wmic.exe" or process.pe.original_file_name == "wmic.exe") and
     process.args : ("group", "useraccount"))
) and not user.id in ("S-1-5-18", "S-1-5-19", "S-1-5-20")
'''

[[rule.threat]]
framework = "MITRE ATT&CK"

[[rule.threat.technique]]
id = "T1069"
name = "Permission Groups Discovery"
reference = "https://attack.mitre.org/techniques/T1069/"

[[rule.threat.technique.subtechnique]]
id = "T1069.001"
name = "Local Groups"
reference = "https://attack.mitre.org/techniques/T1069/001/"

[[rule.threat.technique.subtechnique]]
id = "T1069.002"
name = "Domain Groups"
reference = "https://attack.mitre.org/techniques/T1069/002/"

[[rule.threat.technique]]
id = "T1087"
name = "Account Discovery"
reference = "https://attack.mitre.org/techniques/T1087/"

[[rule.threat.technique.subtechnique]]
id = "T1087.001"
name = "Local Account"
reference = "https://attack.mitre.org/techniques/T1087/001/"

[[rule.threat.technique.subtechnique]]
id = "T1087.002"
name = "Domain Account"
reference = "https://attack.mitre.org/techniques/T1087/002/"

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