YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_MAL_CISA_10365227_01_APPSTORAGE_Dec21

Detects AppStorage ntstatus msexch samples

APT / threat actorAPPSTORAGESignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X

Author: CISA Code & Media Analysis
Date: 2021-12-23
Modified: 2021-12-24
Score / Quality: 80 / 85

What this rule detects

Detects AppStorage ntstatus msexch samples

Associated malware family: APPSTORAGE.

Targets: Windows PE.

It defines 6 patterns (6 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-mal-cisa-10365227-01-appstorage-dec21.yarDetection Rule License 1.1

rule SIGNATURE_BASE_APT_MAL_CISA_10365227_01_APPSTORAGE_Dec21 : APPSTORAGE FILE
{
	meta:
		description = "Detects AppStorage ntstatus msexch samples"
		author = "CISA Code & Media Analysis"
		id = "a44c5609-980f-5961-921c-6b1824cdd49c"
		date = "2021-12-23"
		modified = "2021-12-24"
		reference = "https://www.cisa.gov/uscert/ncas/analysis-reports/ar22-277a"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_stealer_cisa_ar22_277a.yar#L25-L46"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "157a0ffd18e05bfd90a4ec108e5458cbde01015e3407b3964732c9d4ceb71656"
		hash = "30191b3badf3cdbc65d0ffeb68e0f26cef10a41037351b0f562ab52fce7432cc"
		logic_hash = "6a46bc4efa1f22d9fc65d946dbaa7b94de6074e65c228373bb6001f152d5b603"
		score = 80
		quality = 85
		tags = "APPSTORAGE, FILE"
		family = "APPSTORAGE"

	strings:
		$s1 = "026B924DD52F8BE4A3FEE8575DC"
		$s2 = "GetHDDId"
		$s3 = "AppStorage"
		$s4 = "AppDomain"
		$s5 = "$1e3e5580-d264-4c30-89c9-8933c948582c"
		$s6 = "hrjio2mfsdlf235d" wide

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

Strings (6 patterns)

Identifier	Type	Value	Modifiers
$s1	text	"026B924DD52F8BE4A3FEE8575DC"
$s2	text	"GetHDDId"
$s3	text	"AppStorage"
$s4	text	"AppDomain"
$s5	text	"$1e3e5580-d264-4c30-89c9-8933c948582c"
$s6	text	"hrjio2mfsdlf235d"	wide

Condition

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

In plain words (Heuristic)

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

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References

https://www.cisa.gov/uscert/ncas/analysis-reports/ar22-277a

Sample hashes

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

157a0ffd18e05bfd90a4ec108e5458cbde01015e3407b3964732c9d4ceb71656
30191b3badf3cdbc65d0ffeb68e0f26cef10a41037351b0f562ab52fce7432cc

Licence & attribution

Author: CISA Code & Media Analysis

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: a44c5609-980f-5961-921c-6b1824cdd49c

Metadata

family	APPSTORAGE

Tags:APPSTORAGE FILE

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