rule MAL_Passwordstate_Moserware_Backdoor_Apr21_1 {
   meta:
      description = "Detects backdoor used in Passwordstate incident"
      author = "Florian Roth (Nextron Systems)"
      reference = "https://thehackernews.com/2021/04/passwordstate-password-manager-update.html"
      date = "2021-04-25"
      hash1 = "c2169ab4a39220d21709964d57e2eafe4b68c115061cbb64507cfbbddbe635c6"
      hash2 = "f23f9c2aaf94147b2c5d4b39b56514cd67102d3293bdef85101e2c05ee1c3bf9"
      id = "061de3ae-c404-5e4a-a16b-b3b208b1ae7f"
   strings:
      $x1 = "https://passwordstate-18ed2.kxcdn.com" wide

      $s1 = " ProxyUserName, ProxyPassword FROM [SystemSettings]" wide fullword
      $s2 = "PasswordstateService.Passwordstate.Crypto" wide
      $s3 = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.128 Safari" wide fullword

      $op1 = { 00 4c 00 4e 00 43 00 4c 00 49 00 31 00 31 00 3b 00 00 17 }
      $op2 = { 4c 00 49 00 31 00 31 00 3b 00 00 17 50 00 72 00 }
      $op3 = { 61 00 74 00 65 00 2d 00 31 00 38 00 65 00 64 00 32 00 2e 00 6b 00 78 00 }
   condition:
      uint16(0) == 0x5a4d and
      filesize < 200KB and
      1 of ($x*) or 3 of them
}