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DITEKSHEN_MALWARE_Win_Rietspoof

Rietspoof payload

MalwareRietspoofditekSHen detectionBSD 2-Clause LicenseCompiles with YARA-X
Author
ditekSHen
Date
2020-11-06
Modified
2024-11-01
Score / Quality
75 / 73

What this rule detects

Rietspoof payload

Associated malware family: Rietspoof.

Targets: Windows PE.

It defines 19 patterns (19 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

malware-win-rietspoof.yarBSD 2-Clause License
rule DITEKSHEN_MALWARE_Win_Rietspoof : FILE
{
	meta:
		description = "Rietspoof payload"
		author = "ditekSHen"
		id = "b2d94705-ca59-56ae-8471-2c6895d355dc"
		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#L1110-L1140"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "d1d9baab83c904d1e8dcd7aeacdabfc79c1acee67006793c2240a42ebf9c62b2"
		score = 75
		quality = 73
		tags = "FILE"
		clamav_sig = "MALWARE.Win.Trojan.Rietspoof"

	strings:
		$c1 = "%s%s%s USER: user" fullword ascii
		$c2 = "cmd /c %s" fullword ascii
		$c3 = "CreateObject(\"Scripting.FileSystemObject\").DeleteFile(" ascii
		$c4 = "WScript.Quit" fullword ascii
		$c5 = "CPU: %s(%d)" fullword ascii
		$c6 = "RAM: %lld Mb" fullword ascii
		$c7 = "data.dat" fullword ascii
		$c8 = "%s%s%s USER:" ascii
		$v1_1 = ".vbs" ascii
		$v1_2 = "HELLO" ascii
		$v1_3 = "Wscript.Sleep" ascii
		$v1_4 = "User-agent:Mozilla/5.0 (Windows; U;" ascii
		$v2_1 = "Xjoepxt!" ascii
		$v2_2 = "Content-MD5:%s" fullword ascii
		$v2_3 = "M9h5an8f8zTjnyTwQVh6hYBdYsMqHiAz" fullword ascii
		$v2_4 = "GET /%s?%s HTTP/1.1" fullword ascii
		$v2_5 = "GET /?%s HTTP/1.1" fullword ascii
		$pdb1 = "\\techloader\\loader\\loader.odb" ascii wide
		$pdb2 = "\\loader\\Release\\loader_v1.0.pdb" ascii wide

	condition:
		uint16( 0 ) == 0x5a4d and ( 7 of ( $c* ) and ( 3 of ( $v* ) or 1 of ( $pdb* ) ) )
}

Strings (19 patterns)

IdentifierTypeValueModifiers
$c1text"%s%s%s USER: user"fullword ascii
$c2text"cmd /c %s"fullword ascii
$c3text"CreateObject(\"Scripting.FileSystemObject\").DeleteFile("ascii
$c4text"WScript.Quit"fullword ascii
$c5text"CPU: %s(%d)"fullword ascii
$c6text"RAM: %lld Mb"fullword ascii
$c7text"data.dat"fullword ascii
$c8text"%s%s%s USER:"ascii
$v1_1text".vbs"ascii
$v1_2text"HELLO"ascii
$v1_3text"Wscript.Sleep"ascii
$v1_4text"User-agent:Mozilla/5.0 (Windows; U;"ascii
$v2_1text"Xjoepxt!"ascii
$v2_2text"Content-MD5:%s"fullword ascii
$v2_3text"M9h5an8f8zTjnyTwQVh6hYBdYsMqHiAz"fullword ascii
$v2_4text"GET /%s?%s HTTP/1.1"fullword ascii
$v2_5text"GET /?%s HTTP/1.1"fullword ascii
$pdb1text"\\techloader\\loader\\loader.odb"ascii wide
$pdb2text"\\loader\\Release\\loader_v1.0.pdb"ascii wide

Condition

uint16( 0 ) == 0x5a4d and ( 7 of ( $c* ) and ( 3 of ( $v* ) or 1 of ( $pdb* ) ) )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least 7 patterns in ( $c* ) must match.
  • At least 3 patterns in ( $v* ) must match.
  • At least 1 patterns in ( $pdb* ) 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: b2d94705-ca59-56ae-8471-2c6895d355dc

Metadata

clamav_sigMALWARE.Win.Trojan.Rietspoof

Tags:FILE