SUSP_Base64_Encoded_Hex_Encoded_Code

rule SUSP_Base64_Encoded_Hex_Encoded_Code {
   meta:
      author = "Florian Roth (Nextron Systems)"
      description = "Detects hex encoded code that has been base64 encoded"
      date = "2019-04-29"
      score = 65
      reference = "https://www.nextron-systems.com/2019/04/29/spotlight-threat-hunting-yara-rule-example/"
      id = "2cfd278f-ff45-5e23-b552-dad688ab303b"
   strings:
      $x1 = { 78 34 4e ?? ?? 63 65 44 ?? ?? 58 48 67 }
      $x2 = { 63 45 44 ?? ?? 58 48 67 ?? ?? ?? 78 34 4e }

      $fp1 = "Microsoft Azure Code Signp$"
   condition:
      1 of ($x*) and not 1 of ($fp*)
}