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SEKOIA_Apt_Gamaredon_Ddrdoh_Vbs_Downloader

Detects the core of the VBS Gamaredon's Telegram Downloader

APT / threat actorVbsdownloaderSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2023-01-25
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detects the core of the VBS Gamaredon's Telegram Downloader

Associated malware family: Vbsdownloader.

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

Summary generated from the rule's metadata and condition.

Rule source

apt-gamaredon-ddrdoh-vbs-downloader.yarDetection Rule License 1.1
rule SEKOIA_Apt_Gamaredon_Ddrdoh_Vbs_Downloader : FILE
{
	meta:
		description = "Detects the core of the VBS Gamaredon's Telegram Downloader"
		author = "Sekoia.io"
		id = "c934b95d-d81d-4f58-a752-1bb31ba8593d"
		date = "2023-01-25"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_gamaredon_ddrdoh_vbs_downloader.yar#L1-L26"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "940635313b23e29ac98310fc0f20352405c96190d56cd36ef028bf4d6e77fa6b"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$a1 = "==([0-9\\@]+)==" ascii
		$a2 = "data\"\":\"\"(.*?)" ascii
		$a3 = ", vbcr ,\"\")" ascii
		$a4 = ", vblf ,\"\")" ascii
		$a5 = ", \"&&\" ,\"\")" ascii
		$a6 = "ru-RU,ru;q=0.8,en-US;q=0.6,en;q=0.4" ascii
		$b1 = "==([0-9\\@]+)==" base64
		$b2 = "data\"\":\"\"(.*?)" base64
		$b3 = ", vbcr ,\"\")" base64
		$b4 = ", vblf ,\"\")" base64
		$b5 = ", \"&&\" ,\"\")" base64
		$b6 = "ru-RU,ru;q=0.8,en-US;q=0.6,en;q=0.4" base64

	condition:
		(4 of ( $a* ) or 4 of ( $b* ) ) and filesize < 50KB
}

Strings (12 patterns)

IdentifierTypeValueModifiers
$a1text"==([0-9\\@]+)=="ascii
$a2text"data\"\":\"\"(.*?)"ascii
$a3text", vbcr ,\"\")"ascii
$a4text", vblf ,\"\")"ascii
$a5text", \"&&\" ,\"\")"ascii
$a6text"ru-RU,ru;q=0.8,en-US;q=0.6,en;q=0.4"ascii
$b1text"==([0-9\\@]+)=="base64
$b2text"data\"\":\"\"(.*?)"base64
$b3text", vbcr ,\"\")"base64
$b4text", vblf ,\"\")"base64
$b5text", \"&&\" ,\"\")"base64
$b6text"ru-RU,ru;q=0.8,en-US;q=0.6,en;q=0.4"base64

Condition

(4 of ( $a* ) or 4 of ( $b* ) ) and filesize < 50KB

In plain words (Heuristic)

  • The file must be smaller than 50KB (a cheap guard that skips large files).
  • At least 4 patterns in ( $a* ) must match.
  • At least 4 patterns in ( $b* ) must match.

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Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

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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: c934b95d-d81d-4f58-a752-1bb31ba8593d

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE

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