Update RANSOM_Petya_MS17_010

adding rule from https://blueliv.com/petya-ransomware-cyber-attack-is-spreading-across-the-globe-part-2/

malware/RANSOM_Petya_MS17_010

@@ -73,3 +73,22 @@ condition:
       and 9 of ($functions*)
       and 7 of ($cmd*)
 }         
+
+rule petya_eternalblue : petya_eternalblue {
+    meta:
+        author      = "blueliv"
+        description =  "Based on spreading petya version: 2017-06-28"
+        reference = "https://blueliv.com/petya-ransomware-cyber-attack-is-spreading-across-the-globe-part-2/"
+    strings:
+        /* Some commands executed by the Petya variant */
+       $cmd01 = "schtasks %ws/Create /SC once /TN \"\" /TR \"%ws\" /ST %02d:%0" wide
+       $cmd02 = "shutdown.exe /r /f" wide
+       $cmd03 = "%s \\\\%s -accepteula -s" wide
+       $cmd04 = "process call create \"C:\\Windows\\System32\\rundll32.exe \\\"C:\\Windows\\%s\\\" #1" wide
+       /* Strings of encrypted files */
+       $str01 = "they have been encrypted. Perhaps you are busy looking" wide
+        /* MBR/VBR payload */
+        $mbr01 = {00 00 00 55 aa e9 ?? ??}
+    condition:
+        all of them
+}