SUSP_Obfuscated_Powershell_url_encoded_b64

YARA detection rule by Greg Lesnewich · GPL-2.0

look for obfsucated powershell strings obfuscated via url_encoded_b64

rule SUSP_Obfuscated_Powershell_url_encoded_b64 {
  meta:
    author      = "Greg Lesnewich"
    description = "look for obfsucated powershell strings obfuscated via url_encoded_b64"
    date        = "2024-01-31"
    version     = "1.0"
    DaysOfYara  = "32/100"

  strings:
    $powershell_url_encoded_b64 = "70%6f%77%65%72%73%68%65%6c%6c" base64 base64wide
    $PowerShell_url_encoded_b64 = "50%6f%77%65%72%53%68%65%6c%6c" base64 base64wide
    $Powershell_url_encoded_b64 = "50%6f%77%65%72%73%68%65%6c%6c" base64 base64wide

  condition:
    any of them
}

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

a88d8c4c-1c8d-443a-9afb-22aef6b9fa76

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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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