YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_MAL_CISA_10365227_03_Clientuploader_Dec21

Detects ClientUploader onedrv

APT / threat actorSignature 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 ClientUploader onedrv

Targets: Windows PE.

It defines 6 patterns (5 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-mal-cisa-10365227-03-clientuploader-dec21.yarDetection Rule License 1.1

rule SIGNATURE_BASE_APT_MAL_CISA_10365227_03_Clientuploader_Dec21 : FILE
{
	meta:
		description = "Detects ClientUploader onedrv"
		author = "CISA Code & Media Analysis"
		id = "4eeadb28-9312-5602-932a-36acb48772f4"
		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#L4-L23"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "84164e1e8074c2565d3cd178babd93694ce54811641a77ffdc8d1084dd468afb"
		logic_hash = "76f552b2416ae2426b73a321485f34a611c2a3c1ca35791bc9f1834072dc28be"
		score = 80
		quality = 85
		tags = "FILE"

	strings:
		$s1 = "Decoder2"
		$s2 = "ClientUploader"
		$s3 = "AppDomain"
		$s4 = { 5F 49 73 52 65 70 47 ?? 44 65 63 6F 64 65 72 73 }
		$s5 = "LzmaDecoder"
		$s6 = "$ee1b3f3b-b13c-432e-a461-e52d273896a7"

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

Strings (6 patterns)

Identifier	Type	Value
$s1	text	"Decoder2"
$s2	text	"ClientUploader"
$s3	text	"AppDomain"
$s4	hex	{ 5F 49 73 52 65 70 47 ?? 44 65 63 6F 64 65 72 73 }
$s5	text	"LzmaDecoder"
$s6	text	"$ee1b3f3b-b13c-432e-a461-e52d273896a7"

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).

84164e1e8074c2565d3cd178babd93694ce54811641a77ffdc8d1084dd468afb

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: 4eeadb28-9312-5602-932a-36acb48772f4

Tags:FILE

SIGNATURE_BASE_APT_MAL_CISA_10365227_01_APPSTORAGE_Dec21
APT / threat actorSignature Base (Florian Roth / Nextron)· CISA Code & Media Analysis· 2021-12-23
SIGNATURE_BASE_APT_MAL_CISA_10365227_02_Clientuploader_Dec21
APT / threat actorSignature Base (Florian Roth / Nextron)· CISA Code & Media Analysis· 2021-12-23