Skip to content

YARA · Mandiant red team tool countermeasures

FIREEYE_RT_Loader_MSIL_Generic_1

No description has been set in the source file - FireEye-RT

MalwareMandiant red team tool countermeasuresBSD 2-Clause LicenseCompiles with YARA-X
Author
FireEye
Date
2020-12-08
Modified
2020-12-09
Score / Quality
75 / 75

What this rule detects

No description has been set in the source file - FireEye-RT

Targets: Windows PE.

It defines 8 patterns (7 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

loader-msil-generic-1.yarBSD 2-Clause License
rule FIREEYE_RT_Loader_MSIL_Generic_1 : FILE
{
	meta:
		description = "No description has been set in the source file - FireEye-RT"
		author = "FireEye"
		id = "f919e3fc-cf76-53af-8f04-24921830666f"
		date = "2020-12-08"
		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/UNCATEGORIZED/supplemental/yara/Loader_MSIL_Generic_1.yar#L4-L21"
		license_url = "https://github.com/mandiant/red_team_tool_countermeasures//blob/3561b71724dbfa3e2bb78106aaa2d7f8b892c43b/LICENSE.txt"
		hash = "b8415b4056c10c15da5bba4826a44ffd"
		logic_hash = "06cddd7e1c1c778348539cfd50f01d55f86689dec86c045d7ce7b9cd71690e07"
		score = 75
		quality = 75
		tags = "FILE"
		rev = 5

	strings:
		$MSIL = "_CorExeMain"
		$opc1 = { 00 72 [4] 0A 72 [4] 0B 06 28 [4] 0C 12 03 FE 15 [4] 12 04 FE 15 [4] 07 14 }
		$str1 = "DllImportAttribute"
		$str2 = "FromBase64String"
		$str3 = "ResumeThread"
		$str4 = "OpenThread"
		$str5 = "SuspendThread"
		$str6 = "QueueUserAPC"

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

Strings (8 patterns)

IdentifierTypeValueModifiers
$MSILtext"_CorExeMain"
$opc1hex{ 00 72 [4] 0A 72 [4] 0B 06 28 [4] 0C 12 03 FE 15 [4] 12 04 FE 15 [4] 07 14 }
$str1text"DllImportAttribute"
$str2text"FromBase64String"
$str3text"ResumeThread"
$str4text"OpenThread"
$str5text"SuspendThread"
$str6text"QueueUserAPC"

Condition

( uint16( 0 ) == 0x5A4D ) and ( uint32( uint32( 0x3C ) ) == 0x00004550 ) and $MSIL 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.
  • Pattern $MSIL must be present.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

Open in editor

References

Sample hashes

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

  • b8415b4056c10c15da5bba4826a44ffd

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: f919e3fc-cf76-53af-8f04-24921830666f

Metadata

rev5

Tags:FILE