1type: trigger
2name: sigmahq/proc_creation_win_powershell_base64_encoded_obfusc
3description: |
4  Detects suspicious UTF16 and base64 encoded and often obfuscated PowerShell code often used in command lines
5filter: |
6  (evt.Meta.service == 'sysmon' && evt.Parsed.EventID == '1') && (evt.Parsed.CommandLine contains 'IAAtAGIAeABvAHIAIAAwAHgA' || evt.Parsed.CommandLine contains 'AALQBiAHgAbwByACAAMAB4A' || evt.Parsed.CommandLine contains 'gAC0AYgB4AG8AcgAgADAAeA' || evt.Parsed.CommandLine contains 'AC4ASQBuAHYAbwBrAGUAKAApACAAfAAg' || evt.Parsed.CommandLine contains 'AuAEkAbgB2AG8AawBlACgAKQAgAHwAI' || evt.Parsed.CommandLine contains 'ALgBJAG4AdgBvAGsAZQAoACkAIAB8AC' || evt.Parsed.CommandLine contains 'AHsAMQB9AHsAMAB9ACIAIAAtAGYAI' || evt.Parsed.CommandLine contains 'B7ADEAfQB7ADAAfQAiACAALQBmAC' || evt.Parsed.CommandLine contains 'AewAxAH0AewAwAH0AIgAgAC0AZgAg' || evt.Parsed.CommandLine contains 'AHsAMAB9AHsAMwB9ACIAIAAtAGYAI' || evt.Parsed.CommandLine contains 'B7ADAAfQB7ADMAfQAiACAALQBmAC' || evt.Parsed.CommandLine contains 'AewAwAH0AewAzAH0AIgAgAC0AZgAg' || evt.Parsed.CommandLine contains 'AHsAMgB9AHsAMAB9ACIAIAAtAGYAI' || evt.Parsed.CommandLine contains 'B7ADIAfQB7ADAAfQAiACAALQBmAC' || evt.Parsed.CommandLine contains 'AewAyAH0AewAwAH0AIgAgAC0AZgAg' || evt.Parsed.CommandLine contains 'AHsAMQB9AHsAMAB9ACcAIAAtAGYAI' || evt.Parsed.CommandLine contains 'B7ADEAfQB7ADAAfQAnACAALQBmAC' || evt.Parsed.CommandLine contains 'AewAxAH0AewAwAH0AJwAgAC0AZgAg' || evt.Parsed.CommandLine contains 'AHsAMAB9AHsAMwB9ACcAIAAtAGYAI' || evt.Parsed.CommandLine contains 'B7ADAAfQB7ADMAfQAnACAALQBmAC' || evt.Parsed.CommandLine contains 'AewAwAH0AewAzAH0AJwAgAC0AZgAg' || evt.Parsed.CommandLine contains 'AHsAMgB9AHsAMAB9ACcAIAAtAGYAI' || evt.Parsed.CommandLine contains 'B7ADIAfQB7ADAAfQAnACAALQBmAC' || evt.Parsed.CommandLine contains 'AewAyAH0AewAwAH0AJwAgAC0AZgAg')
7blackhole: 2m
8#status: test
9labels:
10  service: windows
11  confidence: 1
12  spoofable: 0
13  classification:
14
15  label: "Suspicious Obfuscated PowerShell Code"
16  behavior : "windows:audit"
17  remediation: false
18
19scope:
20  type: ParentProcessId
21  expression: evt.Parsed.ParentProcessId
22
23