MAL_Msil_Net_NixImports_Loader

YARA detection rule by dr4k0nia · NOASSERTION

Detects NixImports .NET loader

rule MAL_Msil_Net_NixImports_Loader {
   meta:
      description = "Detects NixImports .NET loader"
      author = "dr4k0nia"
      date = "2023-05-21"
      reference = "https://github.com/dr4k0nia/NixImports"
   strings:
      $op_pe = {C2 95 C2 97 C2 B2 C2 92 C2 82 C2 82 C2 8E C2 82 C2 82 C2 82 C2 82 C2 86 C2 82}       $op_delegate = {20 F0 C7 FF 80 20 83 BF 7F 1F 14 14} 
            $a1 = "GetRuntimeProperties" ascii fullword
      $a2 = "GetTypes" ascii fullword
      $a3 = "GetRuntimeMethods" ascii fullword
      $a4 = "netstandard" ascii fullword
   condition:
      uint16(0) == 0x5a4d
      and filesize < 3MB
      and all of ($a*)
      and 2 of ($op*)
}

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

d31b0c54-cf01-46c2-ac1c-bbdb54b45ad9

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

[[ currentRule.title ]]

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