1type: trigger
2name: sigmahq/proc_creation_win_powershell_base64_invoke
3description: |
4  Detects UTF-8 and UTF-16 Base64 encoded powershell 'Invoke-' calls
5filter: |
6  (evt.Meta.service == 'sysmon' && evt.Parsed.EventID == '1') && ((evt.Parsed.Image endsWith '\\powershell.exe' || evt.Parsed.Image endsWith '\\pwsh.exe' || evt.Parsed.OriginalFileName in ['PowerShell.EXE', 'pwsh.dll']) && evt.Parsed.CommandLine contains ' -e' && (evt.Parsed.CommandLine contains 'SQBuAHYAbwBrAGUALQ' || evt.Parsed.CommandLine contains 'kAbgB2AG8AawBlAC0A' || evt.Parsed.CommandLine contains 'JAG4AdgBvAGsAZQAtA' || evt.Parsed.CommandLine contains 'SW52b2tlL' || evt.Parsed.CommandLine contains 'ludm9rZS' || evt.Parsed.CommandLine contains 'JbnZva2Ut'))
7blackhole: 2m
8#status: test
9labels:
10  service: windows
11  confidence: 1
12  spoofable: 0
13  classification:
14   - attack.t1059.001
15   - attack.t1027
16
17  label: "PowerShell Base64 Encoded Invoke Keyword"
18  behavior : "windows:audit"
19  remediation: false
20
21scope:
22  type: ParentProcessId
23  expression: evt.Parsed.ParentProcessId
24
25