YARA · SEKOIA.IO Community

SEKOIA_Apt_Lazarus_Vhd_Ransomware_Loader

Detects VHD ransomware x64 loader

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

Author: Sekoia.io
Date: 2022-11-28
Modified: 2024-12-19
Score / Quality: 75 / 80

What this rule detects

Detects VHD ransomware x64 loader

Associated malware family: Vhd Ransomware.

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-lazarus-vhd-ransomware-loader.yarDetection Rule License 1.1

rule SEKOIA_Apt_Lazarus_Vhd_Ransomware_Loader : FILE
{
	meta:
		description = "Detects VHD ransomware x64 loader "
		author = "Sekoia.io"
		id = "377f3ec5-fa2a-431e-93d2-6a1eb9e01d28"
		date = "2022-11-28"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_lazarus_vhd_ransomware_loader.yar#L1-L30"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "33000fd79b5aae59dcbf445bb4d0d65cf5f939f376a4e3d9e23e14b11ca297da"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$ = { B8 64 [8] B8 75 [8] B8 6D [8] B8 70 [8] B8 2E [8] B8 62 [8] B8 69 [8] B8 6E }
		$ = { 48 63 ?? ?? ??
        48 8B ?? ?? ??
        0F BE ?? ??
        B9 ?? ?? ?? ??
        48 6B ?? ??
        48 8B ?? ?? ??
        0F BE ?? ??
        ?? ??
        48 63 ?? ?? ??
        48 8B ?? ?? ??
        88 ?? ??
        EB }
		$ = { 25 00 73 00 5c [3-15] 25 00 64 00 25 00 64 00 2e 00 62 00 69 00 6e }

	condition:
		uint16be( 0 ) == 0x4d5a and filesize < 200KB and 2 of them
}

Strings (3 patterns)

Identifier	Type	Value
$	hex	{ B8 64 [8] B8 75 [8] B8 6D [8] B8 70 [8] B8 2E [8] B8 62 [8] B8 69 [8] B8 6E }
$	hex	{ 48 63 ?? ?? ?? 48 8B ?? ?? ?? 0F BE ?? ?? B9 ?? ?? ?? ?? 48 6B ?? ?? 48 8B ?? ?? ?? 0F BE ?? ?? ?? ?? …
$	hex	{ 25 00 73 00 5c [3-15] 25 00 64 00 25 00 64 00 2e 00 62 00 69 00 6e }

Condition

uint16be( 0 ) == 0x4d5a and filesize < 200KB and 2 of them

In plain words (Heuristic)

The file must start with “MZ” — a Windows executable (PE).
The file must be smaller than 200KB (a cheap guard that skips large files).
At least 2 patterns in the rule must match.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

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

Open in editor

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: 377f3ec5-fa2a-431e-93d2-6a1eb9e01d28

Metadata

version	1.0
classification	TLP:CLEAR

Tags:FILE

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