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YARA · Volexity threat-intel

VOLEXITY_Apt_Win_Powerstar_Persistence_Batch

Detects the batch script used to persist PowerStar via Startup.

APT / threat actorVolexity threat-intelBSD 2-Clause LicenseCompiles with YARA-X
Author
threatintel@volexity.com
Date
2023-05-16
Modified
2023-09-20
Score / Quality
75 / 80

What this rule detects

Detects the batch script used to persist PowerStar via Startup.

It defines 5 patterns (5 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

apt-win-powerstar-persistence-batch.yarBSD 2-Clause License
rule VOLEXITY_Apt_Win_Powerstar_Persistence_Batch : CHARMINGKITTEN
{
	meta:
		description = "Detects the batch script used to persist PowerStar via Startup."
		author = "threatintel@volexity.com"
		id = "f3ed7b46-d80d-55b1-b6c7-6ea6569f199c"
		date = "2023-05-16"
		modified = "2023-09-20"
		reference = "https://github.com/volexity/threat-intel"
		source_url = "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/2023/2023-06-28 POWERSTAR/indicators/rules.yar#L1-L19"
		license_url = "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/LICENSE.txt"
		hash = "9777f106ac62829cd3cfdbc156100fe892cfc4038f4c29a076e623dc40a60872"
		logic_hash = "9c3a45b759516959eae1cdf8e73bf540b682c90359a6232aa4782a8d1fe15b7d"
		score = 75
		quality = 80
		tags = "CHARMINGKITTEN"
		memory_suitable = 1
		license = "See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt"

	strings:
		$s_1 = "e^c^h^o o^f^f"
		$s_2 = "powershertxdll.ertxdxe"
		$s_3 = "Get-Conrtxdtent -Prtxdath"
		$s_4 = "%appdata%\\Microsrtxdoft\\Windortxdws\\"
		$s_5 = "&(gcm i*x)$"

	condition:
		3 of them
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$s_1text"e^c^h^o o^f^f"
$s_2text"powershertxdll.ertxdxe"
$s_3text"Get-Conrtxdtent -Prtxdath"
$s_4text"%appdata%\\Microsrtxdoft\\Windortxdws\\"
$s_5text"&(gcm i*x)$"

Condition

3 of them

In plain words (Heuristic)

  • At least 3 patterns in the rule must match.

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References

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • 9777f106ac62829cd3cfdbc156100fe892cfc4038f4c29a076e623dc40a60872

Licence & attribution

Author: threatintel@volexity.com

Source repository: Volexity threat-intel @ 3a9d0b5245

Licence: BSD 2-Clause License (stated in the rule's own meta)

“See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt”

Copyright notice: Copyright 2022 by Volexity, Inc.

Original rule

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

Rule id: f3ed7b46-d80d-55b1-b6c7-6ea6569f199c

Metadata

memory_suitable1

Tags:CHARMINGKITTEN