Invoke-Obfuscation VAR++ LAUNCHER OBFUSCATION

 1title: Invoke-Obfuscation VAR++ LAUNCHER OBFUSCATION
 2id: e9f55347-2928-4c06-88e5-1a7f8169942e
 3status: test
 4description: Detects Obfuscated Powershell via VAR++ LAUNCHER
 5references:
 6    - https://github.com/SigmaHQ/sigma/issues/1009 # (Task27)
 7author: Timur Zinniatullin, oscd.community
 8date: 2020/10/13
 9modified: 2022/11/16
10tags:
11    - attack.defense_evasion
12    - attack.t1027
13    - attack.execution
14    - attack.t1059.001
15logsource:
16    category: process_creation
17    product: windows
18detection:
19    selection:
20        # CommandLine|re: '(?i)&&set.*(\{\d\}){2,}\\\"\s+?\-f.*&&.*cmd.*\/c' # FPs with |\/r
21        # Example 1: CMD /C"sET KUR=Invoke-Expression (New-Object Net.WebClient).DownloadString&&Set MxI=C:\wINDowS\sYsWow64\winDOWspoWERSheLl\V1.0\PowerShelL.EXe ${ExEcut`IoN`cON`TExT}.\"invo`kEcoMm`A`ND\".( \"{2}{1}{0}\" -f 'pt','EscRi','INvOk' ).Invoke( ( .( \"{0}{1}\" -f'D','IR' ) ( \"{0}{1}\"-f'ENV:kU','R')).\"vAl`Ue\" )&& CMD /C%mXI%"
22        # Example 2: c:\WiNDOWS\sYSTEm32\CmD.exE /C "sEt DeJLz=Invoke-Expression (New-Object Net.WebClient).DownloadString&&set yBKM=PoWERShelL -noeX ^^^&(\"{2}{0}{1}\"-f '-ItE','m','seT') ( 'V' + 'a'+ 'RiAblE:z8J' +'U2' + 'l' ) ([TYpE]( \"{2}{3}{0}{1}\"-f 'e','NT','e','NViRONM' ) ) ; ^^^& ( ( [sTrIng]${VE`Rbo`SepReFER`Ence})[1,3] + 'X'-joIN'')( ( (.('gI') ('V' + 'a' + 'RIAbLe:z8j' + 'u2' +'l' ) ).vALUe::( \"{2}{5}{0}{1}{6}{4}{3}\" -f 'IRo','Nm','GETE','ABlE','I','nv','enTVAr').Invoke(( \"{0}{1}\"-f'd','ejLz' ),( \"{1}{2}{0}\"-f'cEss','P','RO') )) )&& c:\WiNDOWS\sYSTEm32\CmD.exE /C %ybkm%"
23        CommandLine|contains|all:
24            - '&&set'
25            - 'cmd'
26            - '/c'
27            - '-f'
28        CommandLine|contains:
29            - '{0}'
30            - '{1}'
31            - '{2}'
32            - '{3}'
33            - '{4}'
34            - '{5}'
35    condition: selection
36falsepositives:
37    - Unknown
38level: high