Techniques
Sample rules
New PowerShell Instance Created
- source: sigma
- technicques:
- t1059
- t1059.001
Description
Detects the execution of PowerShell via the creation of a named pipe starting with PSHost
Detection logic
condition: selection
selection:
PipeName|startswith: \PSHost
DNS Server Discovery Via LDAP Query
- source: sigma
- technicques:
- t1482
Description
Detects DNS server discovery via LDAP query requests from uncommon applications
Detection logic
condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
filter_main_defender:
Image|contains: :\ProgramData\Microsoft\Windows Defender\Platform\
Image|endswith: \MsMpEng.exe
filter_main_generic:
Image|contains:
- :\Program Files\
- :\Program Files (x86)\
- :\Windows\
filter_main_null:
Image: null
filter_main_unknown:
Image: <unknown process>
filter_optional_azure:
Image|startswith: C:\WindowsAzure\GuestAgent
filter_optional_browsers:
Image|endswith:
- \chrome.exe
- \firefox.exe
- \opera.exe
selection:
QueryName|startswith: _ldap.
PowerShell Module File Created
- source: sigma
- technicques:
Description
Detects the creation of a new PowerShell module “.psm1”, “.psd1”, “.dll”, “.ps1”, etc.
Detection logic
condition: selection
selection:
Image|endswith:
- \powershell.exe
- \pwsh.exe
TargetFilename|contains:
- \WindowsPowerShell\Modules\
- \PowerShell\7\Modules\
Potential Defense Evasion Via Raw Disk Access By Uncommon Tools
- source: sigma
- technicques:
- t1006
Description
Detects raw disk access using uncommon tools or tools that are located in suspicious locations (heavy filtering is required), which could indicate possible defense evasion attempts
Detection logic
condition: not 1 of filter_main_* and not 1 of filter_optional_*
filter_main_floppy:
Device|contains: floppy
filter_main_generic:
Image|contains:
- :\$WINDOWS.~BT\
- :\Program Files (x86)\
- :\Program Files\
- :\Windows\CCM\
- :\Windows\explorer.exe
- :\Windows\servicing\
- :\Windows\SoftwareDistribution\
- :\Windows\System32\
- :\Windows\SystemApps\
- :\Windows\uus\
- :\Windows\WinSxS\
filter_main_microsoft_appdata:
Image|contains|all:
- :\Users\
- \AppData\
- \Microsoft\
filter_main_null:
Image: null
filter_main_ssd_nvme:
Image|contains: :\Windows\Temp\
Image|endswith:
- \Executables\SSDUpdate.exe
- \HostMetadata\NVMEHostmetadata.exe
filter_main_system_images:
Image:
- Registry
- System
filter_main_systemsettings:
Image|endswith: :\Windows\ImmersiveControlPanel\SystemSettings.exe
filter_main_windefender:
Image|contains: :\ProgramData\Microsoft\Windows Defender\Platform\
Image|endswith: \MsMpEng.exe
filter_optional_Keybase:
Image|contains: \AppData\Local\Keybase\upd.exe
filter_optional_github_desktop:
Image|contains: \AppData\Local\GitHubDesktop\app-
Image|endswith: \resources\app\git\mingw64\bin\git.exe
filter_optional_nextron:
Image|contains: :\Windows\Temp\asgard2-agent\
Image|endswith: \thor.exe
Compressed File Creation Via Tar.EXE
- source: sigma
- technicques:
- t1560
- t1560.001
Description
Detects execution of “tar.exe” in order to create a compressed file. Adversaries may abuse various utilities to compress or encrypt data before exfiltration.
Detection logic
condition: all of selection_*
selection_create:
CommandLine|contains:
- -c
- -r
- -u
selection_img:
- Image|endswith: \tar.exe
- OriginalFileName: bsdtar
File And SubFolder Enumeration Via Dir Command
- source: sigma
- technicques:
- t1217
Description
Detects usage of the “dir” command part of Widows CMD with the “/S” command line flag in order to enumerate files in a specified directory and all subdirectories.
Detection logic
condition: all of selection_*
selection_cli:
CommandLine|contains|windash: dir*-s
selection_cmd:
- Image|endswith: \cmd.exe
- OriginalFileName: Cmd.Exe
Compressed File Extraction Via Tar.EXE
- source: sigma
- technicques:
- t1560
- t1560.001
Description
Detects execution of “tar.exe” in order to extract compressed file. Adversaries may abuse various utilities in order to decompress data to avoid detection.
Detection logic
condition: all of selection_*
selection_extract:
CommandLine|contains: -x
selection_img:
- Image|endswith: \tar.exe
- OriginalFileName: bsdtar
External Disk Drive Or USB Storage Device Was Recognized By The System
- source: sigma
- technicques:
- t1091
- t1200
Description
Detects external disk drives or plugged-in USB devices.
Detection logic
condition: all of selection_*
selection_eid:
EventID: 6416
selection_field:
- ClassName: DiskDrive
- DeviceDescription: USB Mass Storage Device
Locked Workstation
- source: sigma
- technicques:
Description
Detects locked workstation session events that occur automatically after a standard period of inactivity.
Detection logic
condition: selection
selection:
EventID: 4800
PowerShell Script Execution Policy Enabled
- source: sigma
- technicques:
Description
Detects the enabling of the PowerShell script execution policy. Once enabled, this policy allows scripts to be executed.
Detection logic
condition: selection
selection:
Details: DWORD (0x00000001)
TargetObject|endswith: \Policies\Microsoft\Windows\PowerShell\EnableScripts
New ODBC Driver Registered
- source: sigma
- technicques:
Description
Detects the registration of a new ODBC driver.
Detection logic
condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
filter_main_sqlserver:
Details: '%WINDIR%\System32\SQLSRV32.dll'
TargetObject|contains: \SQL Server\
filter_optional_office_access:
Details|endswith: \ACEODBC.DLL
Details|startswith: C:\Progra
TargetObject|contains: '\Microsoft Access '
filter_optional_office_excel:
Details|endswith: \ACEODBC.DLL
Details|startswith: C:\Progra
TargetObject|contains: \Microsoft Excel Driver
selection:
TargetObject|contains: \SOFTWARE\ODBC\ODBCINST.INI\
TargetObject|endswith: \Driver
System Information Discovery - Auditd
- source: sigma
- technicques:
- t1082
Description
Detects System Information Discovery commands
Detection logic
condition: 1 of selection_*
selection_1:
name:
- /etc/lsb-release
- /etc/redhat-release
- /etc/issue
type: PATH
selection_2:
a0:
- uname
- uptime
- lsmod
- hostname
- env
type: EXECVE
selection_3:
a0: grep
a1|contains:
- vbox
- vm
- xen
- virtio
- hv
type: EXECVE
selection_4:
a0: kmod
a1: list
type: EXECVE