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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_VEST_Encryption_Core_Accumulator_Jan21

Detects VEST encryption core accumulator in PE file as used by Lazarus malware

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2021-01-28
Modified
2023-12-05
Score / Quality
70 / 85

What this rule detects

Detects VEST encryption core accumulator in PE file as used by Lazarus malware

Targets: Windows PE.

It defines 1 patterns (0 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

susp-vest-encryption-core-accumulator-jan21.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_VEST_Encryption_Core_Accumulator_Jan21 : FILE
{
	meta:
		description = "Detects VEST encryption core accumulator in PE file as used by Lazarus malware"
		author = "Florian Roth (Nextron Systems)"
		id = "8343652b-8865-5213-b735-d6d4084e4a84"
		date = "2021-01-28"
		modified = "2023-12-05"
		reference = "https://twitter.com/ochsenmeier/status/1354737155495649280"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_lazarus_jan21.yar#L2-L25"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "7cd3ca8bdfb44e98a4b9d0c6ad77546e03d169bda9bdf3d1bcf339f68137af23"
		logic_hash = "41fe42b2f2b5fb54b7ff19b74a35aadd928be9a3c7280ee9feffc4a142924b07"
		score = 70
		quality = 85
		tags = "FILE"

	strings:
		$sc1 = { 4F 70 46 DA E1 8D F6 41 59 E8 5D 26 1E CC 2F 89
               26 6D 52 BA BC 11 6B A9 C6 47 E4 9C 1E B6 65 A2
               B6 CD 90 47 1C DF F8 10 4B D2 7C C4 72 25 C6 97
               25 5D C6 1D 4B 36 BC 38 36 33 F8 89 B4 4C 65 A7
               96 CA 1B 63 C3 4B 6A 63 DC 85 4C 57 EE 2A 05 C7
               0C E7 39 35 8A C1 BF 13 D9 52 51 3D 2E 41 F5 72
               85 23 FE A1 AA 53 61 3B 25 5F 62 B4 36 EE 2A 51
               AF 18 8E 9A C6 CF C4 07 4A 9B 25 9B 76 62 0E 3E
               96 3A A7 64 23 6B B6 19 BC 2D 40 D7 36 3E E2 85
               9A D1 22 9F BC 30 15 9F C2 5D F1 23 E6 3A 73 C0 }

	condition:
		uint16( 0 ) == 0x5a4d and 1 of them
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$sc1hex{ 4F 70 46 DA E1 8D F6 41 59 E8 5D 26 1E CC 2F 89 26 6D 52 BA BC 11 6B A9 C6 47 E4 9C 1E B6 65 A2 B6 CD 90 47 1C DF F8 10 4B D2 7C …

Condition

uint16( 0 ) == 0x5a4d and 1 of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least 1 patterns in the rule must match.

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References

Sample hashes

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

  • 7cd3ca8bdfb44e98a4b9d0c6ad77546e03d169bda9bdf3d1bcf339f68137af23

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: 8343652b-8865-5213-b735-d6d4084e4a84

Tags:FILE