Skip to content
yararules.org
Menu

YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_OBFUSC_Unknown_Jan22_1

Detects samples similar to reversed stage3 found in Ukrainian wiper incident named WhisperGate

MalwareWhispergateSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2022-01-16
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Detects samples similar to reversed stage3 found in Ukrainian wiper incident named WhisperGate

Associated malware family: Whispergate.

Targets: Windows PE.

It defines 7 patterns (2 text, 5 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-obfusc-unknown-jan22-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_OBFUSC_Unknown_Jan22_1 : FILE
{
	meta:
		description = "Detects samples similar to reversed stage3 found in Ukrainian wiper incident named WhisperGate"
		author = "Florian Roth (Nextron Systems)"
		id = "647c0092-b03d-5627-8568-ddaa982c73a1"
		date = "2022-01-16"
		modified = "2023-12-05"
		reference = "https://twitter.com/juanandres_gs/status/1482827018404257792"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_ua_wiper_whispergate.yar#L76-L101"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "9ef7dbd3da51332a78eff19146d21c82957821e464e8133e9594a07d716d892d"
		logic_hash = "26a295d3b78c3a33d776a648aa0f410ac7cb5021ad9d3b294ff9629d6ba7132a"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$xc1 = { 37 00 63 00 38 00 63 00 62 00 35 00 35 00 39 00
               38 00 65 00 37 00 32 00 34 00 64 00 33 00 34 00
               33 00 38 00 34 00 63 00 63 00 65 00 37 00 34 00
               30 00 32 00 62 00 31 00 31 00 66 00 30 00 65 }
		$xc2 = { 4D 61 69 6E 00 43 6C 61 73 73 4C 69 62 72 61 72
               79 31 00 70 63 31 65 }
		$s1 = ".dll" wide
		$s2 = "%&%,%s%" ascii fullword
		$op1 = { a2 87 fa b1 44 a5 f5 12 da a7 49 11 5c 8c 26 d4 75 }
		$op2 = { d7 af 52 38 c7 47 95 c8 0e 88 f3 d5 0b }
		$op3 = { 6c 05 df d6 b8 ac 11 f2 67 16 cb b7 34 4d b6 91 }

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 1000KB and ( 1 of ( $x* ) or 3 of them )
}

Strings (7 patterns)

IdentifierTypeValueModifiers
$xc1hex{ 37 00 63 00 38 00 63 00 62 00 35 00 35 00 39 00 38 00 65 00 37 00 32 00 34 00 64 00 33 00 34 00 33 00 38 00 34 00 63 00 63 00 65 …
$xc2hex{ 4D 61 69 6E 00 43 6C 61 73 73 4C 69 62 72 61 72 79 31 00 70 63 31 65 }
$s1text".dll"wide
$s2text"%&%,%s%"ascii fullword
$op1hex{ a2 87 fa b1 44 a5 f5 12 da a7 49 11 5c 8c 26 d4 75 }
$op2hex{ d7 af 52 38 c7 47 95 c8 0e 88 f3 d5 0b }
$op3hex{ 6c 05 df d6 b8 ac 11 f2 67 16 cb b7 34 4d b6 91 }

Condition

uint16( 0 ) == 0x5a4d and filesize < 1000KB and ( 1 of ( $x* ) or 3 of them )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 1000KB (a cheap guard that skips large files).
  • At least 1 patterns in ( $x* ) must match.
  • At least 3 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

Sample hashes

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

  • 9ef7dbd3da51332a78eff19146d21c82957821e464e8133e9594a07d716d892d

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: 647c0092-b03d-5627-8568-ddaa982c73a1

Tags:FILE

Related rules

More Whispergate rules