Sneed-Reactivity/yara-Neo23x0/gen_vhd_anomaly.yar

rule SUSP_VHD_Suspicious_Small_Size {
   meta:
      description = "Detects suspicious VHD files"
      author = "Florian Roth (Nextron Systems)"
      reference = "https://twitter.com/MeltX0R/status/1208095892877774850"
      date = "2019-12-21"
      modified = "2023-01-27"
      score = 50
      hash1 = "3382a75bd959d2194c4b1a8885df93e8770f4ebaeaff441a5180ceadf1656cd9"
      id = "f4a72e7b-ddd3-5038-9440-1e81dc27755d"
   strings:
      /* VHD */
      $hc1 = { 63 6F 6E 65 63 74 69 78 }
      $hc2a = { 49 6E 76 61 6C 69 64 20 70 61 72 74 69 74 69 6F
               6E 20 74 61 62 6C 65 00 45 72 72 6F 72 20 6C 6F
               61 64 69 6E 67 20 6F 70 65 72 61 74 69 6E 67 20
               73 79 73 74 65 6D 00 4D 69 73 73 69 6E 67 20 6F
               70 65 72 61 74 69 6E 67 20 73 79 73 74 65 6D }
      $hc2b = "connectix"
   condition:
      not uint16(0) == 0x5a4d
      and filesize > 1KB and filesize <= 4000KB 
      and (
         $hc1 at 0 
         or all of ($hc2*)
      )
}