User Account Creation

 1[metadata]
 2creation_date = "2020/02/18"
 3integration = ["endpoint", "windows"]
 4maturity = "production"
 5min_stack_comments = "New fields added: required_fields, related_integrations, setup"
 6min_stack_version = "8.3.0"
 7updated_date = "2024/03/28"
 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 = ["winlogbeat-*", "logs-endpoint.events.process-*", "logs-windows.*", "endgame-*", "logs-system.security*"]
17language = "eql"
18license = "Elastic License v2"
19name = "User Account Creation"
20note = """## Triage and analysis
21
22### Investigating User Account Creation
23
24Attackers may create new accounts (both local and domain) to maintain access to victim systems.
25
26This rule identifies the usage of `net.exe` to create new accounts.
27
28#### Possible investigation steps
29
30- 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.
31- Identify the user account that performed the action and whether it should perform this kind of action.
32- Identify if the account was added to privileged groups or assigned special privileges after creation.
33- Investigate other alerts associated with the user/host during the past 48 hours.
34
35### False positive analysis
36
37- 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.
38
39### Related rules
40
41- Creation of a Hidden Local User Account - 2edc8076-291e-41e9-81e4-e3fcbc97ae5e
42- Windows User Account Creation - 38e17753-f581-4644-84da-0d60a8318694
43
44### Response and remediation
45
46- Initiate the incident response process based on the outcome of the triage.
47- Isolate the involved host to prevent further post-compromise behavior.
48- Delete the created account.
49- 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.
50- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
51- 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).
52"""
53risk_score = 21
54rule_id = "1aa9181a-492b-4c01-8b16-fa0735786b2b"
55setup = """## Setup
56
57If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
58events will not define `event.ingested` and default fallback for EQL rules was not added until version 8.2.
59Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
60`event.ingested` to @timestamp.
61For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
62"""
63severity = "low"
64tags = ["Domain: Endpoint", "OS: Windows", "Use Case: Threat Detection", "Tactic: Persistence", "Resources: Investigation Guide", "Data Source: Elastic Endgame", "Data Source: Elastic Defend"]
65timestamp_override = "event.ingested"
66type = "eql"
67
68query = '''
69process where host.os.type == "windows" and event.type == "start" and
70  process.name : ("net.exe", "net1.exe") and
71  not process.parent.name : "net.exe" and
72  (process.args : "user" and process.args : ("/ad", "/add"))
73'''
74
75
76[[rule.threat]]
77framework = "MITRE ATT&CK"
78[[rule.threat.technique]]
79id = "T1136"
80name = "Create Account"
81reference = "https://attack.mitre.org/techniques/T1136/"
82[[rule.threat.technique.subtechnique]]
83id = "T1136.001"
84name = "Local Account"
85reference = "https://attack.mitre.org/techniques/T1136/001/"
86
87
88
89[rule.threat.tactic]
90id = "TA0003"
91name = "Persistence"
92reference = "https://attack.mitre.org/tactics/TA0003/"