Detect Local Groups in Splunk
Adversaries may attempt to find local system groups and permission settings. The knowledge of local system permission groups can help adversaries determine which groups exist and which users belong to a particular group. Adversaries may use this information to determine which users have elevated permissions, such as the users found within the local administrators group. Commands such as net localgroup of the Net utility, dscl . -list /Groups on macOS, and groups on Linux can list local groups.
MITRE ATT&CK
- Tactic
- Discovery
- Technique
- T1069 Permission Groups Discovery
- Sub-technique
- T1069.001 Local Groups
- Canonical reference
- https://attack.mitre.org/techniques/T1069/001/
SPL Detection Query
index=wineventlog (sourcetype="XmlWinEventLog:Microsoft-Windows-Sysmon/Operational" EventCode=1) OR (sourcetype="WinEventLog:Security" EventCode=4688)
| eval Image=coalesce(Image, NewProcessName)
| eval CommandLine=coalesce(CommandLine, ProcessCommandLine)
| eval ParentImage=coalesce(ParentImage, ParentProcessName)
| eval CommandLine_lower=lower(CommandLine)
| eval Image_lower=lower(Image)
| where (
(match(Image_lower, "(\\\\net\.exe|\\\\net1\.exe)") AND match(CommandLine_lower, "localgroup"))
OR (match(Image_lower, "(\\\\powershell\.exe|\\\\pwsh\.exe)") AND match(CommandLine_lower, "(get-localgroup|get-localgroupmember|localgroup)"))
OR (match(Image_lower, "\\\\wmic\.exe") AND match(CommandLine_lower, "group"))
)
| eval IsAdminGroupQuery=if(match(CommandLine_lower, "(administrators|admin|remote desktop|backup operators|power users)"), 1, 0)
| eval IsNetLocalGroup=if(match(Image_lower, "(net\.exe|net1\.exe)") AND match(CommandLine_lower, "localgroup"), 1, 0)
| eval IsPowerShellLocalGroup=if(match(Image_lower, "(powershell\.exe|pwsh\.exe)") AND match(CommandLine_lower, "(get-localgroup|get-localgroupmember)"), 1, 0)
| eval IsWmicGroup=if(match(Image_lower, "wmic\.exe") AND match(CommandLine_lower, "group"), 1, 0)
| eval SuspiciousParent=if(match(lower(ParentImage), "(cmd\.exe|powershell\.exe|wscript\.exe|cscript\.exe|mshta\.exe|rundll32\.exe|regsvr32\.exe|python\.exe|bash|sh)"), 1, 0)
| eval SuspicionScore=IsAdminGroupQuery + SuspiciousParent
| table _time, host, User, Image, CommandLine, ParentImage, IsAdminGroupQuery, IsNetLocalGroup, IsPowerShellLocalGroup, IsWmicGroup, SuspiciousParent, SuspicionScore
| sort - _timeDetects local group enumeration using Sysmon Event ID 1 (Process Creation) or Security Event ID 4688 (Process Creation with command line auditing). Identifies net.exe/net1.exe with 'localgroup', PowerShell Local Group cmdlets, and WMIC group queries. Assigns a suspicion score based on whether sensitive groups are targeted and whether the parent process is a known LOLBin or scripting host.
Data Sources
Required Sourcetypes
False Positives & Tuning
- IT administrators manually inventorying local group membership during routine system audits or change management
- Endpoint management agents (SCCM, Intune, Tanium, CrowdStrike) that enumerate local groups as part of system inventory or compliance checks
- Vulnerability scanners and security assessment tools (Nessus, Qualys, Rapid7) that enumerate local groups as part of credentialed scans
- Helpdesk scripts and support tools that check local group membership before granting or revoking access
- Legitimate user enumeration during Active Directory domain join procedures or user provisioning workflows
Other platforms for T1069.001
Testing Methodology
Validate this detection against 5 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Enumerate Local Groups with net localgroup
Expected signal: Sysmon Event ID 1: Two Process Create events with Image=C:\Windows\System32\net.exe, CommandLine='net localgroup' and 'net localgroup Administrators'. Security Event ID 4688 (if command line auditing enabled) with NewProcessName=net.exe and ProcessCommandLine containing 'localgroup'. Parent process will be cmd.exe or powershell.exe depending on execution context.
- Test 2Enumerate Local Groups with PowerShell Get-LocalGroup
Expected signal: Sysmon Event ID 1: Two Process Create events with Image=powershell.exe, CommandLines containing 'Get-LocalGroup' and 'Get-LocalGroupMember'. PowerShell ScriptBlock Logging Event ID 4104 in Microsoft-Windows-PowerShell/Operational will capture the full cmdlets. Security Event ID 4688 if command line auditing is enabled.
- Test 3Enumerate Local Groups with WMIC
Expected signal: Sysmon Event ID 1: Two Process Create events with Image=C:\Windows\System32\wbem\wmic.exe, CommandLines containing 'group list brief' and 'group where'. Security Event ID 4688 if command line auditing is enabled. WMI activity may also be captured in Event ID 5857-5861 from Microsoft-Windows-WMI-Activity/Operational.
- Test 4Enumerate Local Groups on Linux with groups and getent
Expected signal: Auditd process creation events (if auditd is configured with -a always,exit -F arch=b64 -S execve rules) for groups, id, getent, and cat processes. Syslog entries if process accounting is enabled. On systems with Sysmon for Linux, Event ID 1 process creation events will be generated.
- Test 5Simulate Turla-style net localgroup output redirection
Expected signal: Sysmon Event ID 1: Process Create for cmd.exe with CommandLine containing 'net localgroup administrators' and output redirection '>>'. Sysmon Event ID 1: Child process net.exe spawned by cmd.exe with CommandLine 'net localgroup administrators'. Sysmon Event ID 11: File Create event for the output file in %TEMP%. Security Event ID 4688 for both cmd.exe and net.exe if process creation auditing is enabled.
References (12)
- https://attack.mitre.org/techniques/T1069/001/
- https://attack.mitre.org/software/S0039/
- https://attack.mitre.org/software/S0521/
- https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/net-localgroup
- https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.localaccounts/get-localgroup
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-deviceprocessevents-table
- https://www.welivesecurity.com/2020/05/26/agentbtz-comrat-ten-years/
- https://www.mandiant.com/resources/blog/admin338
- https://www.microsoft.com/en-us/security/blog/2016/04/29/digging-deep-for-platinum/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1069.001/T1069.001.md
- https://github.com/SigmaHQ/sigma/tree/master/rules/windows/process_creation
- https://www.crowdstrike.com/blog/understanding-active-directory-attack-tools/
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