User Account Creation

  1[metadata]
  2creation_date = "2020/02/18"
  3integration = ["endpoint", "windows", "system", "m365_defender", "sentinel_one_cloud_funnel", "crowdstrike"]
  4maturity = "production"
  5updated_date = "2024/11/02"
  6min_stack_version = "8.14.0"
  7min_stack_comments = "Breaking change at 8.14.0 for the Windows Integration."
  8
  9[rule]
 10author = ["Elastic"]
 11description = """
 12Identifies attempts to create new users. This is sometimes done by attackers to increase access or establish persistence
 13on a system or domain.
 14"""
 15from = "now-9m"
 16index = [
 17    "winlogbeat-*",
 18    "logs-endpoint.events.process-*",
 19    "logs-windows.forwarded*",
 20    "logs-windows.sysmon_operational-*",
 21    "endgame-*",
 22    "logs-system.security*",
 23    "logs-m365_defender.event-*",
 24    "logs-sentinel_one_cloud_funnel.*",
 25    "logs-crowdstrike.fdr*",
 26]
 27language = "eql"
 28license = "Elastic License v2"
 29name = "User Account Creation"
 30note = """## Triage and analysis
 31
 32### Investigating User Account Creation
 33
 34Attackers may create new accounts (both local and domain) to maintain access to victim systems.
 35
 36This rule identifies the usage of `net.exe` to create new accounts.
 37
 38#### Possible investigation steps
 39
 40- 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.
 41- Identify the user account that performed the action and whether it should perform this kind of action.
 42- Identify if the account was added to privileged groups or assigned special privileges after creation.
 43- Investigate other alerts associated with the user/host during the past 48 hours.
 44
 45### False positive analysis
 46
 47- Account creation is a common administrative task, so there is a high chance of the activity being legitimate. Before investigating further, verify that this activity is not benign.
 48
 49### Related rules
 50
 51- Creation of a Hidden Local User Account - 2edc8076-291e-41e9-81e4-e3fcbc97ae5e
 52- Windows User Account Creation - 38e17753-f581-4644-84da-0d60a8318694
 53
 54### Response and remediation
 55
 56- Initiate the incident response process based on the outcome of the triage.
 57- Isolate the involved host to prevent further post-compromise behavior.
 58- Delete the created account.
 59- 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.
 60- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
 61- 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).
 62"""
 63risk_score = 21
 64rule_id = "1aa9181a-492b-4c01-8b16-fa0735786b2b"
 65severity = "low"
 66tags = [
 67    "Domain: Endpoint",
 68    "OS: Windows",
 69    "Use Case: Threat Detection",
 70    "Tactic: Persistence",
 71    "Resources: Investigation Guide",
 72    "Data Source: Elastic Endgame",
 73    "Data Source: Elastic Defend",
 74    "Data Source: System",
 75    "Data Source: Microsoft Defender for Endpoint",
 76    "Data Source: Sysmon",
 77    "Data Source: SentinelOne",
 78    "Data Source: Crowdstrike",
 79]
 80timestamp_override = "event.ingested"
 81type = "eql"
 82
 83query = '''
 84process where host.os.type == "windows" and event.type == "start" and
 85  (process.name : ("net.exe", "net1.exe") and not process.parent.name : "net.exe") and
 86  (process.args : "user" and process.args : ("/ad", "/add"))
 87'''
 88
 89
 90[[rule.threat]]
 91framework = "MITRE ATT&CK"
 92[[rule.threat.technique]]
 93id = "T1136"
 94name = "Create Account"
 95reference = "https://attack.mitre.org/techniques/T1136/"
 96[[rule.threat.technique.subtechnique]]
 97id = "T1136.001"
 98name = "Local Account"
 99reference = "https://attack.mitre.org/techniques/T1136/001/"
100
101
102
103[rule.threat.tactic]
104id = "TA0003"
105name = "Persistence"
106reference = "https://attack.mitre.org/tactics/TA0003/"