SUSP_OfficeDoc_VBA_Base64Decode

rule SUSP_OfficeDoc_VBA_Base64Decode {
   meta:
      description = "Detects suspicious VBA code with Base64 decode functions"
      author = "Florian Roth (Nextron Systems)"
      reference = "https://github.com/cpaton/Scripting/blob/master/VBA/Base64.bas"
      date = "2019-06-21"
      score = 70
      hash1 = "52262bb315fa55b7441a04966e176b0e26b7071376797e35c80aa60696b6d6fc"
      id = "99690116-fc89-53d7-8f29-575d75d53fc9"
   strings:
      $s1 = "B64_CHAR_DICT" ascii
      $s2 = "Base64Decode" ascii
      $s3 = "Base64Encode" ascii
   condition:
      uint16(0) == 0xcfd0 and filesize < 60KB and 2 of them
}