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VOLEXITY_Apt_Malware_Win_Pocostick_Jul23

Detects the July 2023 POCOSTICK variant. These strings are only visible in memory after several rounds of shellcode decryption.

APT / threat actorVolexity threat-intelBSD 2-Clause LicenseCompiles with YARA-X
Author
threatintel@volexity.com
Date
2023-07-24
Modified
2024-08-02
Score / Quality
75 / 80

What this rule detects

Detects the July 2023 POCOSTICK variant. These strings are only visible in memory after several rounds of shellcode decryption.

It defines 8 patterns (8 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

apt-malware-win-pocostick-jul23.yarBSD 2-Clause License
rule VOLEXITY_Apt_Malware_Win_Pocostick_Jul23 : STORMBAMBOO FILE MEMORY
{
	meta:
		description = "Detects the July 2023 POCOSTICK variant. These strings are only visible in memory after several rounds of shellcode decryption."
		author = "threatintel@volexity.com"
		id = "9632a7fc-06da-58b4-b95c-b46aeb9dd41d"
		date = "2023-07-24"
		modified = "2024-08-02"
		reference = "TIB-20231221"
		source_url = "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/2024/2024-08-02 StormBamboo/rules.yar#L206-L235"
		license_url = "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/LICENSE.txt"
		hash = "ec3e787c369ac4b28447e7cacc44d70a595e39d47f842bacb07d19b12cab6aad"
		logic_hash = "19487db733c7f793be2a1287df32a165e46f6af0e940b13b389f4d675b5100c4"
		score = 75
		quality = 80
		tags = "STORMBAMBOO, FILE, MEMORY"
		os = "win"
		os_arch = "all"
		scan_context = "file,memory"
		severity = "critical"
		license = "See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt"
		rule_id = 9542
		version = 3

	strings:
		$str1 = "Folder PATH listing form volume" wide
		$str2 = "Volume serial number is 0000-1111" wide
		$str3 = "Type:Error" wide
		$str4 = "Type:Desktop" wide
		$str5 = "Type:Laptop" wide
		$str6 = "Type:Vitual" wide
		$str7 = ".unicode.tmp" wide
		$str8 = "EveryOne" wide

	condition:
		6 of them
}

Strings (8 patterns)

IdentifierTypeValueModifiers
$str1text"Folder PATH listing form volume"wide
$str2text"Volume serial number is 0000-1111"wide
$str3text"Type:Error"wide
$str4text"Type:Desktop"wide
$str5text"Type:Laptop"wide
$str6text"Type:Vitual"wide
$str7text".unicode.tmp"wide
$str8text"EveryOne"wide

Condition

6 of them

In plain words (Heuristic)

  • At least 6 patterns in the rule must match.

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Sample hashes

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

  • ec3e787c369ac4b28447e7cacc44d70a595e39d47f842bacb07d19b12cab6aad

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: 9632a7fc-06da-58b4-b95c-b46aeb9dd41d

Metadata

oswin
os_archall
scan_contextfile,memory
severitycritical
rule_id9542
version3

Tags:STORMBAMBOOFILEMEMORY