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HvS_APT37_webshell_controllers_asp

YARA detection rule by Moritz Oettle · Detection Rule License 1.1 https://github.com/Neo23x0/signature-base/blob/master/LICENSE

Webshell named controllers.asp or inc-basket-offer.asp used by APT37

rule HvS_APT37_webshell_controllers_asp {
   meta:
      description = "Webshell named controllers.asp or inc-basket-offer.asp used by APT37"
      license = "Detection Rule License 1.1 https://github.com/Neo23x0/signature-base/blob/master/LICENSE"
      author = "Moritz Oettle"
      date = "2020-12-15"
      reference = "https://www.hvs-consulting.de/media/downloads/ThreatReport-Lazarus.pdf"
      hash = "829462fc6d84aae04a962dfc919d0a392265fbf255eab399980d2b021e385517"
      id = "82370415-30f4-514d-8806-e2daced96f07"
   strings:
      $s0 = "<%@Language=VBScript.Encode" ascii
      $x1 = { 64 7F 44 2D 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x2 = { 64 7F 49 2D 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x3 = { 64 7F 49 2D 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x4 = { 64 7F 49 23 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x5 = { 64 7F 49 23 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x6 = { 64 7F 49 23 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x7 = { 64 7F 49 23 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x8 = { 64 41 44 2D 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x9 = { 64 41 44 2D 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x10 = { 64 41 44 2D 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x11 = { 64 41 44 2D 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x12 = { 64 7F 44 2D 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x13 = { 64 41 44 23 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x14 = { 64 41 44 23 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x15 = { 64 41 44 23 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x16 = { 64 41 44 23 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x17 = { 64 41 49 2D 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x18 = { 64 41 49 2D 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x19 = { 64 41 49 2D 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x20 = { 64 41 49 2D 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x21 = { 64 41 49 23 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x22 = { 64 41 49 23 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x23 = { 64 7F 44 2D 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x24 = { 64 41 49 23 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x25 = { 64 41 49 23 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x26 = { 6A 7F 44 2D 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x27 = { 6A 7F 44 2D 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x28 = { 6A 7F 44 2D 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x29 = { 6A 7F 44 2D 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x30 = { 6A 7F 44 23 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x31 = { 6A 7F 44 23 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x32 = { 6A 7F 44 23 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x33 = { 6A 7F 44 23 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x34 = { 64 7F 44 2D 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x35 = { 6A 7F 49 2D 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x36 = { 6A 7F 49 2D 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x37 = { 6A 7F 49 2D 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x38 = { 6A 7F 49 2D 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x39 = { 6A 7F 49 23 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x40 = { 6A 7F 49 23 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x41 = { 6A 7F 49 23 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x42 = { 6A 7F 49 23 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x43 = { 6A 41 44 2D 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x44 = { 6A 41 44 2D 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x45 = { 64 7F 44 23 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x46 = { 6A 41 44 2D 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x47 = { 6A 41 44 2D 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x48 = { 6A 41 44 23 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x49 = { 6A 41 44 23 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x50 = { 6A 41 44 23 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x51 = { 6A 41 44 23 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x52 = { 6A 41 49 2D 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x53 = { 6A 41 49 2D 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x54 = { 6A 41 49 2D 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x55 = { 6A 41 49 2D 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x56 = { 64 7F 44 23 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x57 = { 6A 41 49 23 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x58 = { 6A 41 49 23 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x59 = { 6A 41 49 23 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x60 = { 6A 41 49 23 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x61 = { 64 7F 44 23 41 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x62 = { 64 7F 44 23 41 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x63 = { 64 7F 49 2D 7F 44 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
      $x64 = { 64 7F 49 2D 7F 49 63 2F 6D 4D 6B 61 4F 59 62 3A 6E 72 21 59 }
   condition:
      filesize > 50KB and filesize < 200KB and ( $s0 and 1 of ($x*) )
}

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

7610087e-7ef3-4cdf-af95-5aa13ea11e5a

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

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