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YARA · Mandiant red team tool countermeasures

FIREEYE_RT_APT_Loader_MSIL_PGF_2

base.js, ./lib/payload/techniques/jscriptdotnet/jscriptdotnet_payload.py

APT / threat actorMandiant red team tool countermeasuresBSD 2-Clause LicenseCompiles with YARA-X
Author
FireEye
Date
2020-11-25
Modified
2020-12-09
Score / Quality
75 / 75

What this rule detects

base.js, ./lib/payload/techniques/jscriptdotnet/jscriptdotnet_payload.py

Targets: Windows PE.

It defines 4 patterns (3 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
apt-loader-msil-pgf-2.yarBSD 2-Clause License
rule FIREEYE_RT_APT_Loader_MSIL_PGF_2 : FILE
{
	meta:
		description = "base.js, ./lib/payload/techniques/jscriptdotnet/jscriptdotnet_payload.py"
		author = "FireEye"
		id = "c5f2ec90-cd9b-53ce-893b-e44192fcd507"
		date = "2020-11-25"
		date = "2020-11-25"
		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/PGF/production/yara/APT_Loader_MSIL_PGF_2.yar#L4-L20"
		license_url = "https://github.com/mandiant/red_team_tool_countermeasures//blob/3561b71724dbfa3e2bb78106aaa2d7f8b892c43b/LICENSE.txt"
		hash = "7c2a06ceb29cdb25f24c06f2a8892fba"
		logic_hash = "b962ea30c063009c0383e25edda3a65202bea4496d0d6228549dcea82bba0d03"
		score = 75
		quality = 75
		tags = "FILE"
		rev = 1

	strings:
		$sb1 = { 2? 00 10 00 00 0A 1? 40 0? 72 [4] 0? 0? 28 [2] 00 0A 0? 03 28 [2] 00 0A 74 [2] 00 01 6F [2] 00 0A 03 1? 0? 74 [2] 00 01 28 [2] 00 0A 6? 0? 0? 28 [2] 00 06 D0 [2] 00 01 28 [2] 00 0A 1? 28 [2] 00 0A 79 [2] 00 01 71 [2] 00 01 13 ?? 0? 1? 11 ?? 0? 74 [2] 00 01 28 [2] 00 0A 28 [2] 00 0A 7E [2] 00 0A 13 ?? 1? 13 ?? 7E [2] 00 0A 13 ?? 03 28 [2] 00 0A 74 [2] 00 01 6F [2] 00 0A 03 1? 1? 11 ?? 11 ?? 1? 11 ?? 28 [2] 00 06 }
		$ss1 = "\x00CreateThread\x00"
		$ss2 = "\x00ScriptObjectStackTop\x00"
		$ss3 = "\x00Microsoft.JScript\x00"

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

Strings (4 patterns)

IdentifierTypeValueModifiers
$sb1hex{ 2? 00 10 00 00 0A 1? 40 0? 72 [4] 0? 0? 28 [2] 00 0A 0? 03 28 [2] 00 0A 74 [2] 00 01 6F [2] 00 0A 03 1? 0? 74 [2] 00 01 28 [2] 00 0A 6? 0? 0? 28 [2] 00 06 D0 …
$ss1text"\x00CreateThread\x00"
$ss2text"\x00ScriptObjectStackTop\x00"
$ss3text"\x00Microsoft.JScript\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

Sample hashes

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

  • 7c2a06ceb29cdb25f24c06f2a8892fba

Licence & attribution

Author: FireEye

Source repository: Mandiant red team tool countermeasures @ 3561b71724

Licence: BSD 2-Clause License (repository licence)

Copyright notice: Copyright (c) 2023, MANDIANT

Original rule

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

Rule id: c5f2ec90-cd9b-53ce-893b-e44192fcd507

Metadata

rev1

Tags:FILE

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