MAL_LNX_RedMenshen_BPFDoor_May23_1

YARA detection rule by Florian Roth · NOASSERTION

Detects BPFDoor malware

rule MAL_LNX_RedMenshen_BPFDoor_May23_1 {
   meta:
      description = "Detects BPFDoor malware"
      author = "Florian Roth"
      reference = "https://www.deepinstinct.com/blog/bpfdoor-malware-evolves-stealthy-sniffing-backdoor-ups-its-game"
      date = "2023-05-11"
      score = 80
      hash1 = "afa8a32ec29a31f152ba20a30eb483520fe50f2dce6c9aa9135d88f7c9c511d7"
      id = "25df4dba-ec6e-5999-b6be-56fe933cb0d0"
   strings:
      $x1 = "[-] Execute command failed" ascii fullword
      $x2 = "/var/run/initd.lock" ascii fullword
      
      $xc1 = { 2F 00 3E 3E 00 65 78 69 74 00 72 00 }

      $sc1 = { 9F CD 30 44 }
      $sc2 = { 66 27 14 5E }

      $sa1 = "TLS-CHACHA20-POLY1305-SHA256" ascii fullword

      $sop1 = { 48 83 c0 01 4c 39 f8 75 ea 4c 89 7c 24 68 48 69 c3 d0 00 00 00 48 8b 5c 24 50 48 8b 54 24 78 48 c7 44 24 38 00 00 00 00 }
      $sop2 = { 48 89 de f3 a5 89 03 8b 44 24 2c 39 44 24 28 44 89 4b 04 48 89 53 10 0f 95 c0 }
      $sop3 = { 49 d3 cd 4d 31 cd b1 29 49 89 e9 49 d3 c8 4d 31 c5 4c 03 68 10 48 89 f9 }
   condition:
            uint16(0) == 0x457f and
      filesize < 900KB and (
         ( 1 of ($x*) and 1 of ($s*) )
         or 4 of them
         
         or ( 
            all of ($sc*) 
            and $sc1 in (@sc2[1]-50..@sc2[1]+50) 
         )
            ) or (
         2 of ($x*)
         or 5 of them
      )
}

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

f66a49d4-528c-41a1-8767-a95c8728a987

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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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