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Suspicious_Size_spoolsv_exe

YARA detection rule by Florian Roth (Nextron Systems) · Detection Rule License 1.1 https://github.com/Neo23x0/signature-base/blob/master/LICENSE

Detects uncommon file size of spoolsv.exe

rule Suspicious_Size_spoolsv_exe {
   meta:
      description = "Detects uncommon file size of spoolsv.exe"
      license = "Detection Rule License 1.1 https://github.com/Neo23x0/signature-base/blob/master/LICENSE"
      author = "Florian Roth (Nextron Systems)"
      score = 60
      date = "2015-12-23"
      modified = "2025-03-17"
      noarchivescan = 1
      id = "14bb3463-b99f-57e1-8cff-fe9a34771093"
   condition:
      uint16(0) == 0x5a4d
      and filename == "spoolsv.exe"
      and (filesize < 50KB or filesize > 1500KB)
}

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

20558c06-0793-4879-a36f-fc228e2c00e9

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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

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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.

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What do these messages mean?

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

[[ currentRule.title ]]

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