/*
   Yara Rule Set
   Author: Florian Roth
   Date: 2017-05-12
   Identifier: WannaCry
   Reference: https://goo.gl/HG2j5T
*/

/* Rule Set ----------------------------------------------------------------- */

rule WannaCry_Ransomware {
   meta:
      description = "Detects WannaCry Ransomware"
      author = "Florian Roth (with the help of binar.ly)"
      reference = "https://goo.gl/HG2j5T"
      date = "2017-05-12"
      hash1 = "ed01ebfbc9eb5bbea545af4d01bf5f1071661840480439c6e5babe8e080e41aa"
   strings:
      $x1 = "icacls . /grant Everyone:F /T /C /Q" fullword ascii
      $x2 = "taskdl.exe" fullword ascii
      $x3 = "tasksche.exe" fullword ascii
      $x4 = "Global\\MsWinZonesCacheCounterMutexA" fullword ascii
      $x5 = "WNcry@2ol7" fullword ascii
      $x6 = "www.iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com" ascii
      $x7 = "mssecsvc.exe" fullword ascii
      $x8 = "C:\\%s\\qeriuwjhrf" fullword ascii
      $x9 = "icacls . /grant Everyone:F /T /C /Q" fullword ascii

      $s1 = "C:\\%s\\%s" fullword ascii
      $s2 = "<!-- Windows 10 --> " fullword ascii
      $s3 = "cmd.exe /c \"%s\"" fullword ascii
      $s4 = "msg/m_portuguese.wnry" fullword ascii
      $s5 = "\\\\192.168.56.20\\IPC$" fullword wide
      $s6 = "\\\\172.16.99.5\\IPC$" fullword wide

      $op1 = { 10 ac 72 0d 3d ff ff 1f ac 77 06 b8 01 00 00 00 }
      $op2 = { 44 24 64 8a c6 44 24 65 0e c6 44 24 66 80 c6 44 }
      $op3 = { 18 df 6c 24 14 dc 64 24 2c dc 6c 24 5c dc 15 88 }
      $op4 = { 09 ff 76 30 50 ff 56 2c 59 59 47 3b 7e 0c 7c }
      $op5 = { c1 ea 1d c1 ee 1e 83 e2 01 83 e6 01 8d 14 56 }
      $op6 = { 8d 48 ff f7 d1 8d 44 10 ff 23 f1 23 c1 }
   condition:
      uint16(0) == 0x5a4d and filesize < 10000KB and ( 1 of ($x*) and 1 of ($s*) or 3 of ($op*) )
}

rule WannaCry_Ransomware_Gen {
   meta:
      description = "Detects WannaCry Ransomware"
      author = "Florian Roth (based on rule by US CERT)"
      reference = "https://www.us-cert.gov/ncas/alerts/TA17-132A"
      date = "2017-05-12"
      hash1 = "9fe91d542952e145f2244572f314632d93eb1e8657621087b2ca7f7df2b0cb05"
      hash2 = "8e5b5841a3fe81cade259ce2a678ccb4451725bba71f6662d0cc1f08148da8df"
      hash3 = "4384bf4530fb2e35449a8e01c7e0ad94e3a25811ba94f7847c1e6612bbb45359"
   strings:
      $s1 = "__TREEID__PLACEHOLDER__" fullword ascii
      $s2 = "__USERID__PLACEHOLDER__" fullword ascii
      $s3 = "Windows for Workgroups 3.1a" fullword ascii
      $s4 = "PC NETWORK PROGRAM 1.0" fullword ascii
      $s5 = "LANMAN1.0" fullword ascii
   condition:
      uint16(0) == 0x5a4d and filesize < 5000KB and all of them
}

rule WannCry_m_vbs {
   meta:
      description = "Detects WannaCry Ransomware VBS"
      license = "https://creativecommons.org/licenses/by-nc/4.0/"
      author = "Florian Roth"
      reference = "https://goo.gl/HG2j5T"
      date = "2017-05-12"
      hash1 = "51432d3196d9b78bdc9867a77d601caffd4adaa66dcac944a5ba0b3112bbea3b"
   strings:
      $x1 = ".TargetPath = \"C:\\@" ascii
      $x2 = ".CreateShortcut(\"C:\\@" ascii
      $s3 = " = WScript.CreateObject(\"WScript.Shell\")" ascii
   condition:
      ( uint16(0) == 0x4553 and filesize < 1KB and all of them )
}

rule WannCry_BAT {
   meta:
      description = "Detects WannaCry Ransomware BATCH File"
      license = "https://creativecommons.org/licenses/by-nc/4.0/"
      author = "Florian Roth"
      reference = "https://goo.gl/HG2j5T"
      date = "2017-05-12"
      hash1 = "f01b7f52e3cb64f01ddc248eb6ae871775ef7cb4297eba5d230d0345af9a5077"
   strings:
      $s1 = "@.exe\">> m.vbs" ascii
      $s2 = "cscript.exe //nologo m.vbs" fullword ascii
      $s3 = "echo SET ow = WScript.CreateObject(\"WScript.Shell\")> " ascii
      $s4 = "echo om.Save>> m.vbs" fullword ascii
   condition:
      ( uint16(0) == 0x6540 and filesize < 1KB and 1 of them )
}

rule WannaCry_RansomNote {
   meta:
      description = "Detects WannaCry Ransomware Note"
      license = "https://creativecommons.org/licenses/by-nc/4.0/"
      author = "Florian Roth"
      reference = "https://goo.gl/HG2j5T"
      date = "2017-05-12"
      hash1 = "4a25d98c121bb3bd5b54e0b6a5348f7b09966bffeec30776e5a731813f05d49e"
   strings:
      $s1 = "A:  Don't worry about decryption." fullword ascii
      $s2 = "Q:  What's wrong with my files?" fullword ascii
   condition:
      ( uint16(0) == 0x3a51 and filesize < 2KB and all of them )
}

/* Kaspersky Rule */

rule APT_lazaruswannacry {
   meta:
      description = "Rule based on shared code between Feb 2017 Wannacry sample and Lazarus backdoor from Feb 2015 discovered by Neel Mehta"
      date = "2017-05-15"
      reference = "https://twitter.com/neelmehta/status/864164081116225536"
      author = "Costin G. Raiu, Kaspersky Lab"
      version = "1.0"
      hash = "9c7c7149387a1c79679a87dd1ba755bc"
      hash = "ac21c8ad899727137c4b94458d7aa8d8"
   strings:
      $a1 = { 51 53 55 8B 6C 24 10 56 57 6A 20 8B 45 00 8D 75
         04 24 01 0C 01 46 89 45 00 C6 46 FF 03 C6 06 01 46
         56 E8 }
      $a2 = { 03 00 04 00 05 00 06 00 08 00 09 00 0A 00 0D 00
         10 00 11 00 12 00 13 00 14 00 15 00 16 00 2F 00
         30 00 31 00 32 00 33 00 34 00 35 00 36 00 37 00
         38 00 39 00 3C 00 3D 00 3E 00 3F 00 40 00 41 00
         44 00 45 00 46 00 62 00 63 00 64 00 66 00 67 00
         68 00 69 00 6A 00 6B 00 84 00 87 00 88 00 96 00
         FF 00 01 C0 02 C0 03 C0 04 C0 05 C0 06 C0 07 C0
         08 C0 09 C0 0A C0 0B C0 0C C0 0D C0 0E C0 0F C0
         10 C0 11 C0 12 C0 13 C0 14 C0 23 C0 24 C0 27 C0
         2B C0 2C C0 FF FE }
   condition:
      uint16(0) == 0x5A4D and filesize < 15000000 and all of them
}