powershell_base64_encoded_shellcode

rule powershell_base64_encoded_shellcode {
 meta:
    author = "Florian Roth"
    description = "Detects Base64 encoded Shellcode  License: https://github.com/Neo23x0/sigma/blob/master/LICENSE.Detection.Rules.md."
    reference = "https://tdm.socprime.com/tdm/info/RtwpJThpBzv8"
    version = "0.01"
    created = "2018/11/17"
    category = "process_creation"
    product = "windows"
    mitre = "defense_evasion, t1036"

  events:
(re.regex($selection1.target.process.command_line, `.*AAAAYInlM.*`) and ($selection1.metadata.product_event_type = "4688" or $selection1.metadata.product_event_type = "1") and (re.regex($selection1.target.process.command_line, `.*OiCAAAAYInlM.*`) or re.regex($selection1.target.process.command_line, `.*OiJAAAAYInlM.*`)))

  condition:
    $selection1
}