APT_APT29_NOBELIUM_JS_EnvyScout_May21_1_RID33E3

YARA detection rule by Florian Roth · CC-BY-NC https://creativecommons.org/licenses/by-nc/4.0/

Detects EnvyScout deobfuscator code as used by NOBELIUM group

rule APT_APT29_NOBELIUM_JS_EnvyScout_May21_1_RID33E3 : APT DEMO G0016 G0118 RUSSIA T1059_007 {
   meta:
      description = "Detects EnvyScout deobfuscator code as used by NOBELIUM group"
      author = "Florian Roth"
      reference = "https://www.microsoft.com/security/blog/2021/05/28/breaking-down-nobeliums-latest-early-stage-toolset/"
      date = "2021-05-29 15:07:01"
      score = 75
      customer = "demo"
      license = "CC-BY-NC https://creativecommons.org/licenses/by-nc/4.0/"
      
      tags = "APT, DEMO, G0016, G0118, RUSSIA, T1059_007"
      minimum_yara = "3.5.0"
      
   strings:
      $x1 = "[i].charCodeAt(0) ^ 2);}" 
   condition: 
      filesize < 5000KB and 1 of them
}

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

215cbc1c-f7d1-46fb-adb9-d46d2ec3518f

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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 ]]

What do these messages mean?

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

[[ currentRule.title ]]

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