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SEKOIA_Apt_Polonium_Megacreep_Strings

Tries to detect POLONIUM's MegaCreep implant

APT / threat actorSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2022-10-12
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Tries to detect POLONIUM's MegaCreep implant

Targets: Windows PE.

It defines 12 patterns (12 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
apt-polonium-megacreep-strings.yarDetection Rule License 1.1
rule SEKOIA_Apt_Polonium_Megacreep_Strings : FILE
{
	meta:
		description = "Tries to detect POLONIUM's MegaCreep implant"
		author = "Sekoia.io"
		id = "4d62d5bc-2ec9-58ef-bfe7-c0b04fa73b6f"
		date = "2022-10-12"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_polonium_megacreep_strings.yar#L1-L28"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "f4881e15854b082d8e6b8a28a7eb1518c559577b1b3ce76e404d67b1fe723fde"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"
		orig_id = "927c5fd6-0574-43bf-8db9-6ecc328estrin56c7"

	strings:
		$ = "[#!#]" ascii wide
		$ = "[$$%$$]" ascii wide
		$ = ".e##x##e" ascii wide
		$ = "WHLib.dll" ascii wide
		$ = "TestService.txt" ascii wide
		$ = "X = Stop" ascii wide
		$ = "Sess.dll" ascii wide
		$ = "filepathOnTarget" ascii wide
		$ = "FileNameOnMega" ascii wide
		$ = "Missing Parameter.. Format of command:" ascii wide
		$ = "Your Old K##E##Y is Wronge" ascii wide
		$ = "Your Upgrage Is Success" ascii wide

	condition:
		uint16be( 0 ) == 0x4d5a and filesize < 2MB and 3 of them
}

Strings (12 patterns)

IdentifierTypeValueModifiers
$text"[#!#]"ascii wide
$text"[$$%$$]"ascii wide
$text".e##x##e"ascii wide
$text"WHLib.dll"ascii wide
$text"TestService.txt"ascii wide
$text"X = Stop"ascii wide
$text"Sess.dll"ascii wide
$text"filepathOnTarget"ascii wide
$text"FileNameOnMega"ascii wide
$text"Missing Parameter.. Format of command:"ascii wide
$text"Your Old K##E##Y is Wronge"ascii wide
$text"Your Upgrage Is Success"ascii wide

Condition

uint16be( 0 ) == 0x4d5a and filesize < 2MB and 3 of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 2MB (a cheap guard that skips large files).
  • At least 3 patterns in the rule must match.

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References

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: 4d62d5bc-2ec9-58ef-bfe7-c0b04fa73b6f

Metadata

version1.0
classificationTLP:CLEAR
orig_id927c5fd6-0574-43bf-8db9-6ecc328estrin56c7

Tags:FILE

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