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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_APT_NK_Andariel_Scheduledtask_Loader

Detects a scheduled task loader used by Andariel

MalwareSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
CISA.gov
Date
2024-07-25
Modified
2026-01-29
Score / Quality
80 / 85

What this rule detects

Detects a scheduled task loader used by Andariel

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
mal-apt-nk-andariel-scheduledtask-loader.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_APT_NK_Andariel_Scheduledtask_Loader : FILE
{
	meta:
		description = "Detects a scheduled task loader used by Andariel"
		author = "CISA.gov"
		id = "0c32758b-480c-5784-b28f-cee85d038850"
		date = "2024-07-25"
		modified = "2026-01-29"
		reference = "https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-207a"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_nk_andariel_jul24.yar#L3-L18"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "2d32ee777cb40c6fa58787e92c0de074ea5b81d629a17ccb4f9432d62436f03c"
		score = 80
		quality = 85
		tags = "FILE"

	strings:
		$obfuscation1 = { B8 02 00 00 00 48 6B C0 00 B9 CD FF 00 00 66 89 8C 04 60 01 00 00 B8 02 00 00 00 48 6B C0 01 B9 CC FF 00 00 66 89 8C 04 60 01 00 00 B8 02 00 00 00 48 6B C0 02 B9 8D FF 00 00 66 89 8C 04 60 01 00 00 B8 02 00 00 00 48 6B C0 03 B9 9A FF 00 00 66 89 8C 04 60 01 00 00 B8 02 00 00 00 48 6B C0 04 B9 8C FF 00 00 66 89 8C 04 60 01 00 00 B8 02 00 00 00 48 6B C0 05 B9 8A FF 00 00 66 89 8C 04 60 01 00 00 B8 02 00 00 00 48 6B C0 06 33 C9 66 89 8C 04 60 01 00 00 }
		$obfuscation2 = { 48 6B C0 02 C6 44 04 20 BA B8 01 00 00 00 48 6B C0 03 C6 44 04 20 9A B8 01 00 00 00 48 6B C0 04 C6 44 04 20 8B B8 01 00 00 00 48 6B C0 05 C6 44 04 20 8A B8 01 00 00 00 48 6B C0 06 C6 44 04 20 9C B8 01 00 00 00 }
		$obfuscation3 = { 48 6B C0 00 C6 44 04 20 A8 B8 01 00 00 00 48 6B C0 01 C6 44 04 20 9A B8 01 00 00 00 48 6B C0 02 C6 44 04 20 93 B8 01 00 00 00 48 6B C0 03 C6 44 04 20 96 B8 01 00 00 00 48 6B C0 04 C6 44 04 20 B9 B8 01 00 00 00 48 6B C0 05 C6 44 04 20 9A B8 01 00 00 00 48 6B C0 06 C6 44 04 20 8B B8 01 00 00 00 48 6B C0 07 C6 44 04 20 9E B8 01 00 00 00 48 6B C0 08 C6 44 04 20 9A B8 01 00 00 00 48 6B C0 09 C6 44 04 20 8D B8 01 00 00 00 48 6B C0 0A C6 44 04 20 BC B8 01 00 00 00 }

	condition:
		uint16( 0 ) == 0x5A4D and $obfuscation1 and $obfuscation2 and $obfuscation3
}

Strings (3 patterns)

IdentifierTypeValueModifiers
$obfuscation1hex{ B8 02 00 00 00 48 6B C0 00 B9 CD FF 00 00 66 89 8C 04 60 01 00 00 B8 02 00 00 00 48 6B C0 01 B9 CC FF 00 00 66 89 8C 04 60 01 00 00 B8 02 00 00 00 48 6B C0 02 …
$obfuscation2hex{ 48 6B C0 02 C6 44 04 20 BA B8 01 00 00 00 48 6B C0 03 C6 44 04 20 9A B8 01 00 00 00 48 6B C0 04 C6 44 04 20 8B B8 01 00 00 00 48 6B C0 05 C6 44 04 20 8A B8 01 …
$obfuscation3hex{ 48 6B C0 00 C6 44 04 20 A8 B8 01 00 00 00 48 6B C0 01 C6 44 04 20 9A B8 01 00 00 00 48 6B C0 02 C6 44 04 20 93 B8 01 00 00 00 48 6B C0 03 C6 44 04 20 96 B8 01 …

Condition

uint16( 0 ) == 0x5A4D and $obfuscation1 and $obfuscation2 and $obfuscation3

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • Pattern $obfuscation1 must be present.
  • Pattern $obfuscation2 must be present.
  • Pattern $obfuscation3 must be present.

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References

Licence & attribution

Author: CISA.gov

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: 0c32758b-480c-5784-b28f-cee85d038850

Tags:FILE

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