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DITEKSHEN_MALWARE_Win_Vbsdownloader

Detects second stage VBS downloader of third stage VBS

MalwareVbsdownloaderditekSHen 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 second stage VBS downloader of third stage VBS

Associated malware family: Vbsdownloader.

It defines 5 patterns (5 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

malware-win-vbsdownloader.yarBSD 2-Clause License
rule DITEKSHEN_MALWARE_Win_Vbsdownloader : FILE
{
	meta:
		description = "Detects second stage VBS downloader of third stage VBS"
		author = "ditekShen"
		id = "480e6872-3a8c-58c5-a455-02342ec7918c"
		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#L11363-L11375"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "fee9a78e60d02ff2f03035812af2bf36fe350c70d3e4e094713791833f8ba4d6"
		score = 75
		quality = 75
		tags = "FILE"

	strings:
		$s1 = "CreateObject(\"MSXML2.ServerXMLHTTP\")" wide
		$s2 = ".Open \"GET\"," wide
		$s3 = ".Send" wide
		$s4 = ".responseText" wide
		$s5 = "ExecuteGlobal" wide

	condition:
		filesize < 50KB and all of them
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$s1text"CreateObject(\"MSXML2.ServerXMLHTTP\")"wide
$s2text".Open \"GET\","wide
$s3text".Send"wide
$s4text".responseText"wide
$s5text"ExecuteGlobal"wide

Condition

filesize < 50KB and all of them

In plain words (Heuristic)

  • The file must be smaller than 50KB (a cheap guard that skips large files).
  • All patterns in the rule must match.

Test this rule in your browser

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

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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: 480e6872-3a8c-58c5-a455-02342ec7918c

Tags:FILE

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