Suspicious_PowerShell_AssemblyLoader

YARA detection rule by k3rnelcallz · MIT

Detects PowerShell scripts loading assemblies from memory and hiding payloads

rule Suspicious_PowerShell_AssemblyLoader
{
    meta:
        description = "Detects PowerShell scripts loading assemblies from memory and hiding payloads"
        author = "k3rnelcallz"
        sha256 = "56e0cfc0fb789f7d8d7cef0b8497eef95563f46bb383d5f38061347657eaa445"
		source = "malwarebazaar"
        creation_date = "1-12-25"
		last_modified = "2-12-25"
		source = "Malwarebazaar"
		category = "Info"

    strings:
                $load = "[System.Reflection.Assembly]::Load"
        $invoke = ".Invoke("

                $getProcess = "Get-Process"
        $mz_b64 = "TVqQAAMAAAAEAAAA"

                $aspnet_compiler = "Aspnet_compiler.exe"

                $blackhawk = "BLACKHAWK.DOWN"
        $shoot     = "SHOOT"

    condition:
                $load and $invoke
                and ($getProcess or $mz_b64)
                and any of ($blackhawk,$shoot,$aspnet_compiler)
}

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

59f93437-fc69-481e-9fc0-b9d4a1238b0f

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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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