YARA · Mandiant red team tool countermeasures

FIREEYE_RT_APT_Dropper_Win_MATRYOSHKA_1

matryoshka_dropper.rs

APT / threat actorMandiant red team tool countermeasuresBSD 2-Clause LicenseCompiles with YARA-X

Author: FireEye
Date: 2020-12-02
Modified: 2020-12-09
Score / Quality: 75 / 75

What this rule detects

matryoshka_dropper.rs

Targets: Windows PE.

It defines 4 patterns (4 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-dropper-win-matryoshka-1.yarBSD 2-Clause License

rule FIREEYE_RT_APT_Dropper_Win_MATRYOSHKA_1 : FILE
{
	meta:
		description = "matryoshka_dropper.rs"
		author = "FireEye"
		id = "7fd305c7-0b1b-5d91-b968-7f1fb0a8ae47"
		date = "2020-12-02"
		date = "2020-12-02"
		modified = "2020-12-09"
		reference = "https://github.com/mandiant/red_team_tool_countermeasures/"
		source_url = "https://github.com/mandiant/red_team_tool_countermeasures//blob/3561b71724dbfa3e2bb78106aaa2d7f8b892c43b/rules/MATRYOSHKA/production/yara/APT_Dropper_Win_MATRYOSHKA_1.yar#L4-L20"
		license_url = "https://github.com/mandiant/red_team_tool_countermeasures//blob/3561b71724dbfa3e2bb78106aaa2d7f8b892c43b/LICENSE.txt"
		hash = "edcd58ba5b1b87705e95089002312281"
		logic_hash = "a7bf7599ec9b4b1d09a8c90b70ae565a9396fb31d449da3c1492d6fa336d9c5e"
		score = 75
		quality = 75
		tags = "FILE"
		rev = 1

	strings:
		$s1 = "\x00matryoshka.exe\x00"
		$s2 = "\x00Unable to write data\x00"
		$s3 = "\x00Error while spawning process. NTStatus: \x0a\x00"
		$s4 = "\x00.execmdstart/Cfailed to execute process\x00"

	condition:
		( uint16( 0 ) == 0x5A4D ) and ( uint32( uint32( 0x3C ) ) == 0x00004550 ) and all of them
}

Strings (4 patterns)

Identifier	Type	Value
$s1	text	"\x00matryoshka.exe\x00"
$s2	text	"\x00Unable to write data\x00"
$s3	text	"\x00Error while spawning process. NTStatus: \x0a\x00"
$s4	text	"\x00.execmdstart/Cfailed to execute process\x00"

Condition

( uint16( 0 ) == 0x5A4D ) and ( uint32( uint32( 0x3C ) ) == 0x00004550 ) 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://github.com/mandiant/red_team_tool_countermeasures/

Sample hashes

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

edcd58ba5b1b87705e95089002312281

Licence & attribution

Author: FireEye

Source repository: Mandiant red team tool countermeasures @ 3561b71724

Licence: BSD 2-Clause License (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: 7fd305c7-0b1b-5d91-b968-7f1fb0a8ae47

Metadata

rev	1

Tags:FILE

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