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DITEKSHEN_MALWARE_Win_Covenantgruntstager

Detects Covenant Grunt Stager

MalwareCovenantgruntstagerditekSHen detectionBSD 2-Clause LicenseCompiles with YARA-X
Author
ditekSHen
Date
2020-11-06
Modified
2024-11-01
Score / Quality
75 / 75

What this rule detects

Detects Covenant Grunt Stager

Associated malware family: Covenantgruntstager.

Targets: Windows PE.

It defines 14 patterns (14 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
malware-win-covenantgruntstager.yarBSD 2-Clause License
rule DITEKSHEN_MALWARE_Win_Covenantgruntstager : FILE
{
	meta:
		description = "Detects Covenant Grunt Stager"
		author = "ditekSHen"
		id = "61495541-ed9c-5227-aa50-cbaeacfb20a2"
		date = "2020-11-06"
		modified = "2024-11-01"
		reference = "https://github.com/ditekshen/detection"
		source_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/yara/malware.yar#L5585-L5606"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "638f63f605b21154f062b0f4d0659cd6cd87aee319debb2c1a991a679fec087a"
		score = 75
		quality = 75
		tags = "FILE"

	strings:
		$x1 = "VXNlci1BZ2VudA" ascii wide
		$x2 = "cGFnZT17R1VJRH0mdj0x" ascii wide
		$x3 = "0eXBlPXtHVUlEfSZ2PTE" ascii wide
		$x4 = "tZXNzYWdlPXtHVUlEfSZ2PTE" ascii wide
		$x5 = "L2VuLXVzL" ascii wide
		$x6 = "L2VuLXVzL2luZGV4Lmh0bWw" ascii wide
		$x7 = "L2VuLXVzL2RvY3MuaHRtbD" ascii wide
		$s1 = "ExecuteStager" ascii
		$s2 = "UseCertPinning" fullword ascii
		$s3 = "FromBase64String" fullword ascii
		$s4 = "ToBase64String" fullword ascii
		$s5 = "DownloadString" fullword ascii
		$s6 = "UploadString" fullword ascii
		$s7 = "GetWebRequest" fullword ascii

	condition:
		uint16( 0 ) == 0x5a4d and ( 2 of ( $x* ) or all of ( $s* ) or ( 1 of ( $x* ) and 5 of ( $s* ) ) )
}

Strings (14 patterns)

IdentifierTypeValueModifiers
$x1text"VXNlci1BZ2VudA"ascii wide
$x2text"cGFnZT17R1VJRH0mdj0x"ascii wide
$x3text"0eXBlPXtHVUlEfSZ2PTE"ascii wide
$x4text"tZXNzYWdlPXtHVUlEfSZ2PTE"ascii wide
$x5text"L2VuLXVzL"ascii wide
$x6text"L2VuLXVzL2luZGV4Lmh0bWw"ascii wide
$x7text"L2VuLXVzL2RvY3MuaHRtbD"ascii wide
$s1text"ExecuteStager"ascii
$s2text"UseCertPinning"fullword ascii
$s3text"FromBase64String"fullword ascii
$s4text"ToBase64String"fullword ascii
$s5text"DownloadString"fullword ascii
$s6text"UploadString"fullword ascii
$s7text"GetWebRequest"fullword ascii

Condition

uint16( 0 ) == 0x5a4d and ( 2 of ( $x* ) or all of ( $s* ) or ( 1 of ( $x* ) and 5 of ( $s* ) ) )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in ( $s* ) must match.
  • At least 2 patterns in ( $x* ) must match.
  • At least 1 patterns in ( $x* ) must match.
  • At least 5 patterns in ( $s* ) must match.

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References

Licence & attribution

Author: ditekSHen

Source repository: ditekSHen detection @ e76c93dcde

Licence: BSD 2-Clause License (repository licence)

Copyright notice: Copyright 2021 by ditekSHen (https://github.com/ditekshen/detection).

Original rule

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

Rule id: 61495541-ed9c-5227-aa50-cbaeacfb20a2

Tags:FILE

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