Detection rules › Kusto
DEV-0270 New User Creation
The following query tries to detect creation of a new user using a known DEV-0270 username/password schema
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | T1098 Account Manipulation |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body kusto
id: 7965f0be-c039-4d18-8ee8-9a6add8aecf3
name: DEV-0270 New User Creation
description: |
'The following query tries to detect creation of a new user using a known DEV-0270 username/password schema'
severity: High
requiredDataConnectors:
- connectorId: SecurityEvents
dataTypes:
- SecurityEvent
- connectorId: WindowsSecurityEvents
dataTypes:
- SecurityEvent
- connectorId: MicrosoftThreatProtection
dataTypes:
- DeviceProcessEvents
queryFrequency: 6h
queryPeriod: 6h
triggerOperator: gt
triggerThreshold: 0
status: Available
tactics:
- Persistence
relevantTechniques:
- T1098
tags:
- Dev-0270
query: |
(union isfuzzy=true
(SecurityEvent
| where EventID == 4688
| where CommandLine has_all ('net user', '/add')
| parse CommandLine with * "user " username " "*
| extend password = extract(@"\buser\s+[^\s]+\s+([^\s]+)", 1, CommandLine)
| where username in('DefaultAccount') or password in('P@ssw0rd1234', '_AS_@1394')
| project TimeGenerated, Computer, Account, AccountDomain, ProcessName, ProcessNameFullPath = NewProcessName, EventID, Activity, CommandLine, EventSourceName, Type
),
(DeviceProcessEvents
| where InitiatingProcessCommandLine has_all('net user', '/add')
| parse InitiatingProcessCommandLine with * "user " username " "*
| extend password = extract(@"\buser\s+[^\s]+\s+([^\s]+)", 1, InitiatingProcessCommandLine)
| where username in('DefaultAccount') or password in('P@ssw0rd1234', '_AS_@1394')
| extend Account = strcat(InitiatingProcessAccountDomain, @'\', InitiatingProcessAccountName), Computer = DeviceName
)
)
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| extend AccountName = tostring(split(Account, @'\')[1]), AccountNTDomain = tostring(split(Account, @'\')[0])
entityMappings:
- entityType: Account
fieldMappings:
- identifier: FullName
columnName: Account
- identifier: Name
columnName: AccountName
- identifier: NTDomain
columnName: AccountNTDomain
- entityType: Host
fieldMappings:
- identifier: FullName
columnName: Computer
- identifier: HostName
columnName: HostName
- identifier: DnsDomain
columnName: HostNameDomain
version: 1.0.3
kind: Scheduled
Stages and Predicates
union isfuzzy=true (2 sources)
Each leg below queries one source; the rule matches if any leg does. Sources: SecurityEvent, DeviceProcessEvents
Leg 1: SecurityEvent
SecurityEvent
| where EventID == 4688
| where CommandLine has_all ('net user', '/add')
| parse CommandLine with * "user " username " "*
| extend password = extract(@"\buser\s+[^\s]+\s+([^\s]+)", 1, CommandLine)
| where username in('DefaultAccount') or password in('P@ssw0rd1234', '_AS_@1394')
| project TimeGenerated, Computer, Account, AccountDomain, ProcessName, ProcessNameFullPath = NewProcessName, EventID, Activity, CommandLine, EventSourceName, Type
Leg 2: DeviceProcessEvents
DeviceProcessEvents
| where InitiatingProcessCommandLine has_all('net user', '/add')
| parse InitiatingProcessCommandLine with * "user " username " "*
| extend password = extract(@"\buser\s+[^\s]+\s+([^\s]+)", 1, InitiatingProcessCommandLine)
| where username in('DefaultAccount') or password in('P@ssw0rd1234', '_AS_@1394')
| extend Account = strcat(InitiatingProcessAccountDomain, @'\', InitiatingProcessAccountName), Computer = DeviceName
Applied to the combined result
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| extend AccountName = tostring(split(Account, @'\')[1]), AccountNTDomain = tostring(split(Account, @'\')[0])
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
CommandLine | match |
|
EventID | eq |
|
InitiatingProcessCommandLine | match |
|
password | in |
|
username | in |
|
Output fields
Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.
| Field | Source |
|---|---|
Account | extend |
AccountDomain | project |
Activity | project |
CommandLine | project |
Computer | extend |
EventID | project |
EventSourceName | project |
ProcessName | project |
ProcessNameFullPath | project |
TimeGenerated | project |
Type | project |
password | extend |
DomainIndex | extend |
HostName | extend |
HostNameDomain | extend |
AccountNTDomain | extend |
AccountName | extend |