Skip to content
yararules.org
Menu

YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_WIPER_Isaacwiper_Mar22_1

Detects IsaacWiper malware

MalwareIsaacwiperSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2022-03-03
Modified
2023-12-05
Score / Quality
85 / 85

What this rule detects

Detects IsaacWiper malware

Associated malware family: Isaacwiper.

Targets: Windows PE.

It defines 7 patterns (4 text, 3 hex, 0 regex). YARA modules used: pe.

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

Includes the imports needed to compile it on its own.

mal-wiper-isaacwiper-mar22-1.yarDetection Rule License 1.1
import "pe"

rule SIGNATURE_BASE_MAL_WIPER_Isaacwiper_Mar22_1 : FILE
{
	meta:
		description = "Detects IsaacWiper malware"
		author = "Florian Roth (Nextron Systems)"
		id = "97d8d8dd-db65-5156-8f97-56c620cf2d56"
		date = "2022-03-03"
		modified = "2023-12-05"
		reference = "https://www.welivesecurity.com/2022/03/01/isaacwiper-hermeticwizard-wiper-worm-targeting-ukraine/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_ua_isaacwiper.yar#L3-L29"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "13037b749aa4b1eda538fda26d6ac41c8f7b1d02d83f47b0d187dd645154e033"
		hash = "7bcd4ec18fc4a56db30e0aaebd44e2988f98f7b5d8c14f6689f650b4f11e16c0"
		logic_hash = "6fe7d1536db5fc30c9b4a171be66993fc69e6a1d96dae00be4170bdb4a53afb8"
		score = 85
		quality = 85
		tags = "FILE"

	strings:
		$s1 = "C:\\ProgramData\\log.txt" wide fullword
		$s2 = "Cleaner.dll" ascii fullword
		$s3 = "-- system logical drive: " wide fullword
		$s4 = "-- FAILED" wide fullword
		$op1 = { 8b f1 80 3d b0 66 03 10 00 0f 85 96 00 00 00 33 c0 40 b9 a8 66 03 10 87 01 33 db }
		$op2 = { 8b 40 04 2b c2 c1 f8 02 3b c8 74 34 68 a2 c8 01 10 2b c1 6a 04 }
		$op3 = { 8d 4d f4 ff 75 08 e8 12 ff ff ff 68 88 39 03 10 8d 45 f4 50 e8 2d 1d 00 00 cc }

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 700KB and ( pe.imphash ( ) == "a4b162717c197e11b76a4d9bc58ea25d" or 3 of them )
}

Strings (7 patterns)

IdentifierTypeValueModifiers
$s1text"C:\\ProgramData\\log.txt"wide fullword
$s2text"Cleaner.dll"ascii fullword
$s3text"-- system logical drive: "wide fullword
$s4text"-- FAILED"wide fullword
$op1hex{ 8b f1 80 3d b0 66 03 10 00 0f 85 96 00 00 00 33 c0 40 b9 a8 66 03 10 87 01 33 db }
$op2hex{ 8b 40 04 2b c2 c1 f8 02 3b c8 74 34 68 a2 c8 01 10 2b c1 6a 04 }
$op3hex{ 8d 4d f4 ff 75 08 e8 12 ff ff ff 68 88 39 03 10 8d 45 f4 50 e8 2d 1d 00 00 cc }

Condition

uint16( 0 ) == 0x5a4d and filesize < 700KB and ( pe.imphash ( ) == "a4b162717c197e11b76a4d9bc58ea25d" or 3 of them )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 700KB (a cheap guard that skips large files).
  • At least 3 patterns in the rule must match.
  • Uses the pe module.
  • Checks the PE import hash (imphash).

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

Sample hashes

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

  • 13037b749aa4b1eda538fda26d6ac41c8f7b1d02d83f47b0d187dd645154e033
  • 7bcd4ec18fc4a56db30e0aaebd44e2988f98f7b5d8c14f6689f650b4f11e16c0

Licence & attribution

Author: Florian Roth (Nextron Systems)

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

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: 97d8d8dd-db65-5156-8f97-56c620cf2d56

Tags:FILE

Related rules

More Isaacwiper rules