EXPL_Follina_CVE_2022_30190_Msdt_MSProtocolURI_May22

rule EXPL_Follina_CVE_2022_30190_Msdt_MSProtocolURI_May22 {
   meta:
      description = "Detects the malicious usage of the ms-msdt URI as seen in CVE-2022-30190 / Follina exploitation"
      author = "Tobias Michalski, Christian Burkard"
      date = "2022-05-30"
      modified = "2022-07-18"
      reference = "https://doublepulsar.com/follina-a-microsoft-office-code-execution-vulnerability-1a47fce5629e"
      hash1 = "4a24048f81afbe9fb62e7a6a49adbd1faf41f266b5f9feecdceb567aec096784"
      hash2 = "778cbb0ee4afffca6a0b788a97bc2f4855ceb69ddc5eaa230acfa2834e1aeb07"
      score = 80
      id = "62e67c25-a420-5dac-9d1c-b0648ea6b574"
   strings:
      $re1 = /location\.href\s{0,20}=\s{0,20}"ms-msdt:/
      $a1 = "%6D%73%2D%6D%73%64%74%3A%2F" ascii /* URL encoded "ms-msdt:/" */
   condition:
      filesize > 3KB and
      filesize < 100KB and
      1 of them
}

rule SUSP_Doc_RTF_OLE2Link_Jun22 {
   meta:
      description = "Detects a suspicious pattern in RTF files which downloads external resources"
      author = "Christian Burkard"
      date = "2022-06-01"
      reference = "Internal Research"
      hash = "4abc20e5130b59639e20bd6b8ad759af18eb284f46e99a5cc6b4f16f09456a68"
      score = 75
      id = "e9c83d58-6214-51d5-882a-4bd2ed6acc9a"
   strings:
      $sa = "\\objdata" ascii nocase

      $sb1 = "4f4c45324c696e6b" ascii /* OLE2Link */
      $sb2 = "4F4C45324C696E6B" ascii

      $sc1 = "d0cf11e0a1b11ae1" ascii /* docfile magic - doc file albilae */
      $sc2 = "D0CF11E0A1B11AE1" ascii

      $x1 = "68007400740070003a002f002f00" ascii /* http:// */
      $x2 = "68007400740070003A002F002F00" ascii
      $x3 = "680074007400700073003a002f002f00" ascii /* https:// */
      $x4 = "680074007400700073003A002F002F00" ascii
      $x5 = "6600740070003a002f002f00" ascii /* ftp:// */
      $x6 = "6600740070003A002F002F00" ascii
      /* TODO: more protocols */
   condition:
      ( uint32be(0) == 0x7B5C7274 or uint32be(0) == 0x7B5C2A5C ) /* RTF */
      and $sa
      and 1 of ($sb*)
      and 1 of ($sc*)
      and 1 of ($x*)
}

rule SUSP_Doc_RTF_OLE2Link_EMAIL_Jun22 {
   meta:
      description = "Detects a suspicious pattern in RTF files which downloads external resources inside e-mail attachments"
      author = "Christian Burkard"
      date = "2022-06-01"
      reference = "Internal Research"
      hash = "4abc20e5130b59639e20bd6b8ad759af18eb284f46e99a5cc6b4f16f09456a68"
      score = 75
      id = "48cde505-3ce4-52ef-b338-0c08ac4f63de"
   strings:
      /* \objdata" */
      $sa1 = "XG9iamRhdG" ascii
      $sa2 = "xvYmpkYXRh" ascii
      $sa3 = "cb2JqZGF0Y" ascii

      /* OLE2Link */
      $sb1 = "NGY0YzQ1MzI0YzY5NmU2Y" ascii
      $sb2 = "RmNGM0NTMyNGM2OTZlNm" ascii
      $sb3 = "0ZjRjNDUzMjRjNjk2ZTZi" ascii
      $sb4 = "NEY0QzQ1MzI0QzY5NkU2Q" ascii
      $sb5 = "RGNEM0NTMyNEM2OTZFNk" ascii
      $sb6 = "0RjRDNDUzMjRDNjk2RTZC" ascii

      /* docfile magic - doc file albilae */
      $sc1 = "ZDBjZjExZTBhMWIxMWFlM" ascii
      $sc2 = "QwY2YxMWUwYTFiMTFhZT" ascii
      $sc3 = "kMGNmMTFlMGExYjExYWUx" ascii
      $sc4 = "RDBDRjExRTBBMUIxMUFFM" ascii
      $sc5 = "QwQ0YxMUUwQTFCMTFBRT" ascii
      $sc6 = "EMENGMTFFMEExQjExQUUx" ascii

      /* http:// */
      $x1 = "NjgwMDc0MDA3NDAwNzAwMDNhMDAyZjAwMmYwM" ascii
      $x2 = "Y4MDA3NDAwNzQwMDcwMDAzYTAwMmYwMDJmMD" ascii
      $x3 = "2ODAwNzQwMDc0MDA3MDAwM2EwMDJmMDAyZjAw" ascii
      $x4 = "NjgwMDc0MDA3NDAwNzAwMDNBMDAyRjAwMkYwM" ascii
      $x5 = "Y4MDA3NDAwNzQwMDcwMDAzQTAwMkYwMDJGMD" ascii
      $x6 = "2ODAwNzQwMDc0MDA3MDAwM0EwMDJGMDAyRjAw" ascii
      /* https:// */
      $x7 = "NjgwMDc0MDA3NDAwNzAwMDczMDAzYTAwMmYwMDJmMD" ascii
      $x8 = "Y4MDA3NDAwNzQwMDcwMDA3MzAwM2EwMDJmMDAyZjAw" ascii
      $x9 = "2ODAwNzQwMDc0MDA3MDAwNzMwMDNhMDAyZjAwMmYwM" ascii
      $x10 = "NjgwMDc0MDA3NDAwNzAwMDczMDAzQTAwMkYwMDJGMD" ascii
      $x11 = "Y4MDA3NDAwNzQwMDcwMDA3MzAwM0EwMDJGMDAyRjAw" ascii
      $x12 = "2ODAwNzQwMDc0MDA3MDAwNzMwMDNBMDAyRjAwMkYwM" ascii
      /* ftp:// */
      $x13 = "NjYwMDc0MDA3MDAwM2EwMDJmMDAyZjAw" ascii
      $x14 = "Y2MDA3NDAwNzAwMDNhMDAyZjAwMmYwM" ascii
      $x15 = "2NjAwNzQwMDcwMDAzYTAwMmYwMDJmMD" ascii
      $x16 = "NjYwMDc0MDA3MDAwM0EwMDJGMDAyRjAw" ascii
      $x17 = "Y2MDA3NDAwNzAwMDNBMDAyRjAwMkYwM" ascii
      $x18 = "2NjAwNzQwMDcwMDAzQTAwMkYwMDJGMD" ascii
      /* TODO: more protocols */
   condition:
      filesize < 10MB
      and 1 of ($sa*)
      and 1 of ($sb*)
      and 1 of ($sc*)
      and 1 of ($x*)
}