SUSP_OneNote_Repeated_FileDataReference_Feb23

YARA detection rule by delivr.to

Repeated references to files embedded in OneNote file. May indicate multiple copies of file hidden under image, as leveraged by Qakbot et al.

rule SUSP_OneNote_Repeated_FileDataReference_Feb23 {
   meta:
      description = "Repeated references to files embedded in OneNote file. May indicate multiple copies of file hidden under image, as leveraged by Qakbot et al."
      author = "delivr.to"
      date = "2023-02-17"
      score = 60
   strings:
      
      $one = { E4 52 5C 7B 8C D8 A7 4D AE B1 53 78 D0 29 96 D3 }

      
      $fdso = { 00 e7 16 e3 bd 65 26 11 45 a4 c4 8d 4d 0b 7a 9e ac }

      
      
      $fref = { 3C 00 69 00 66 00 6E 00 64 00 66 00 3E 00 7B 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 2D 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 2D 00 ?? 00 ?? 00 ?? 00 ?? 00 2D 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? 00 ?? }

   condition:
      filesize < 5MB and
      ($one at 0) and 
      $fdso and
      #fref > (#fdso * 4)
}

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

420e3fa4-e762-4357-bbac-410e82c5c2da

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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 ]]

What does this mean?

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 ]]

What do these messages mean?

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

[[ currentRule.title ]]

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