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SEKOIA_Ransomware_Win_Shrinklocker

Detects files related to the ShrinkLocker ransomware

MalwareShrinklockerSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2024-06-07
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detects files related to the ShrinkLocker ransomware

Associated malware family: Shrinklocker.

It defines 11 patterns (11 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

ransomware-win-shrinklocker.yarDetection Rule License 1.1
rule SEKOIA_Ransomware_Win_Shrinklocker
{
	meta:
		description = "Detects files related to the ShrinkLocker ransomware"
		author = "Sekoia.io"
		id = "93a6fbdd-ad62-456a-a1a5-b5ae3b242004"
		date = "2024-06-07"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/ransomware_win_shrinklocker.yar#L1-L25"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "7770b0946b9bb482f23c4ce0d753393e0d42a6fd8b31029847d74356296f0cf1"
		score = 75
		quality = 80
		tags = ""
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$a = "shrinkdisk" ascii fullword
		$b = "BitLocker" ascii fullword
		$c = "diskpart" ascii fullword
		$d = "disk.vbs" ascii fullword
		$e = "strDriveLetter" ascii fullword
		$f = "shrinkcomplate" ascii fullword
		$g = "ADODB.Stream" ascii fullword
		$h = "Win32_OperatingSystem" ascii fullword
		$i = "HKLM\\System\\CurrentControlSet\\Control\\Terminal Server" ascii fullword
		$j = "HKLM\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System" ascii fullword
		$k = "HKLM\\SOFTWARE\\Policies\\Microsoft\\FVE" ascii fullword

	condition:
		9 of them
}

Strings (11 patterns)

IdentifierTypeValueModifiers
$atext"shrinkdisk"ascii fullword
$btext"BitLocker"ascii fullword
$ctext"diskpart"ascii fullword
$dtext"disk.vbs"ascii fullword
$etext"strDriveLetter"ascii fullword
$ftext"shrinkcomplate"ascii fullword
$gtext"ADODB.Stream"ascii fullword
$htext"Win32_OperatingSystem"ascii fullword
$itext"HKLM\\System\\CurrentControlSet\\Control\\Terminal Server"ascii fullword
$jtext"HKLM\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System"ascii fullword
$ktext"HKLM\\SOFTWARE\\Policies\\Microsoft\\FVE"ascii fullword

Condition

9 of them

In plain words (Heuristic)

  • At least 9 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: 93a6fbdd-ad62-456a-a1a5-b5ae3b242004

Metadata

version1.0
classificationTLP:CLEAR