BKDR_XZUtil_Binary_CVE_2024_3094_Mar24_1

YARA detection rule by Florian Roth · NOASSERTION

Detects injected code used by the backdoored XZ library (xzutil) CVE-2024-3094.

rule BKDR_XZUtil_Binary_CVE_2024_3094_Mar24_1 {
   meta:
      description = "Detects injected code used by the backdoored XZ library (xzutil) CVE-2024-3094."
      author = "Florian Roth"
      reference = "https://www.openwall.com/lists/oss-security/2024/03/29/4"
      date = "2024-03-30"
      score = 75
      hash1 = "319feb5a9cddd81955d915b5632b4a5f8f9080281fb46e2f6d69d53f693c23ae"
      hash2 = "605861f833fc181c7cdcabd5577ddb8989bea332648a8f498b4eef89b8f85ad4"
      hash3 = "8fa641c454c3e0f76de73b7cc3446096b9c8b9d33d406d38b8ac76090b0344fd"
      hash4 = "b418bfd34aa246b2e7b5cb5d263a640e5d080810f767370c4d2c24662a274963"
      hash5 = "cbeef92e67bf41ca9c015557d81f39adaba67ca9fb3574139754999030b83537"
      hash6 = "5448850cdc3a7ae41ff53b433c2adbd0ff492515012412ee63a40d2685db3049"
      id = "6ccdeb6d-67c4-5358-a76b-aef7f047c997"
   strings:
      $op1 = { 48 8d 7c 24 08 f3 ab 48 8d 44 24 08 48 89 d1 4c 89 c7 48 89 c2 e8 ?? ?? ?? ?? 89 c2 }
      $op2 = { 31 c0 49 89 ff b9 16 00 00 00 4d 89 c5 48 8d 7c 24 48 4d 89 ce f3 ab 48 8d 44 24 48 }
      $op3 = { 4d 8b 6c 24 08 45 8b 3c 24 4c 8b 63 10 89 85 78 f1 ff ff 31 c0 83 bd 78 f1 ff ff 00 f3 ab 79 07 }

      
      $xc1 = { F3 0F 1E FA 55 48 89 F5 4C 89 CE 53 89 FB 81 E7 00 00 00 80 48 83 EC 28 48 89 54 24 18 48 89 4C 24 10 }
   condition:
      uint16(0) == 0x457f
      and (
         all of ($op*)
         or $xc1
      )
}

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

8142e9f0-30bc-4abe-acc4-7e125a3cc94c

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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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