YARA · SEKOIA.IO Community

SEKOIA_Apt_Cloudatlas_Powershower_Obfuscated

Detects obfuscated version of PowerShower

APT / threat actorSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X

Author: Sekoia.io
Date: 2022-11-29
Modified: 2024-12-19
Score / Quality: 75 / 80

What this rule detects

Detects obfuscated version of PowerShower

It defines 3 patterns (3 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-cloudatlas-powershower-obfuscated.yarDetection Rule License 1.1

rule SEKOIA_Apt_Cloudatlas_Powershower_Obfuscated : FILE
{
	meta:
		description = "Detects obfuscated version of PowerShower"
		author = "Sekoia.io"
		id = "f76ab9d8-7753-4a17-aedd-fc9c3b8cd322"
		date = "2022-11-29"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_cloudatlas_powershower_obfuscated.yar#L1-L18"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "fdb1edb3982eb5356cdf5fd1fa9fcc41d5048848b2a05589e87836ac0b05ec7a"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$s1 = "{0}{1}{2}{3}{4}{5}{6}{7}{8}" ascii wide
		$s2 = "{000}{001}{002}{003}{004}{005}{006}{007}{008}" ascii wide
		$s3 = "::Unicode.GetString([System.Convert]::FromBase64String(" ascii wide

	condition:
		($s1 in ( 0 .. 100 ) or $s2 in ( 0 .. 100 ) ) and $s3 in ( filesize -200 .. filesize )
}

Strings (3 patterns)

Identifier	Type	Value	Modifiers
$s1	text	"{0}{1}{2}{3}{4}{5}{6}{7}{8}"	ascii wide
$s2	text	"{000}{001}{002}{003}{004}{005}{006}{007}{008}"	ascii wide
$s3	text	"::Unicode.GetString([System.Convert]::FromBase64String("	ascii wide

Condition

($s1 in ( 0 .. 100 ) or $s2 in ( 0 .. 100 ) ) and $s3 in ( filesize -200 .. filesize )

In plain words (Heuristic)

Pattern $s1 must be found within the range 0 .. 100.
Pattern $s2 must be found within the range 0 .. 100.
Pattern $s3 must be found within the range filesize -200 .. filesize.

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References

https://github.com/SEKOIA-IO/Community

Licence & attribution

Author: Sekoia.io

Source repository: SEKOIA.IO Community @ a438a5901a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: f76ab9d8-7753-4a17-aedd-fc9c3b8cd322

Metadata

version	1.0
classification	TLP:CLEAR

Tags:FILE

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