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DITEKSHEN_MALWARE_Win_Cratpluginscreencapture

Detects CRAT Screen Capture plugin DLL

MalwareCratpluginscreencaptureditekSHen 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 CRAT Screen Capture plugin DLL

Associated malware family: Cratpluginscreencapture.

Targets: Windows PE.

It defines 12 patterns (10 text, 0 hex, 2 regex).

Summary generated from the rule's metadata and condition.

Rule source

malware-win-cratpluginscreencapture.yarBSD 2-Clause License
rule DITEKSHEN_MALWARE_Win_Cratpluginscreencapture : FILE
{
	meta:
		description = "Detects CRAT Screen Capture plugin DLL"
		author = "ditekSHen"
		id = "ef0b6b88-8b1b-5ab5-ad81-276eaff0411f"
		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#L1981-L2000"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "7b4378ae883d01338fabe2eb50a5509b722c661e63afc287afa07b263a0ebc42"
		score = 75
		quality = 75
		tags = "FILE"

	strings:
		$ai1 = "VM detected!" fullword wide
		$ai2 = "Sandbox detected!" fullword wide
		$ai3 = "Debug detected!" fullword wide
		$ai4 = "Analysis process detected!" fullword wide
		$s1 = "User is inactive!, give up capture" wide
		$s2 = "Capturing screen..." wide
		$s3 = "%s\\P%02d%lu.tmp" fullword wide
		$s4 = "CloseHandle ScreenCaptureMutex failure! %d" fullword wide
		$s5 = "ScreenCaptureMutex already created! %s" fullword wide
		$s6 = "Create ScreenCaptureMutex %s failure %d" fullword wide
		$s7 = /ScreenCaptureThread\s(finished|terminated)!/ wide
		$s8 = /ScreenCapture_(x64|x32|Win64|Win32)_DllRelease\.dll/ fullword ascii

	condition:
		uint16( 0 ) == 0x5a4d and ( ( all of ( $ai* ) and 1 of ( $s* ) ) or ( 3 of ( $s* ) and 1 of ( $ai* ) ) or 6 of them )
}

Strings (12 patterns)

IdentifierTypeValueModifiers
$ai1text"VM detected!"fullword wide
$ai2text"Sandbox detected!"fullword wide
$ai3text"Debug detected!"fullword wide
$ai4text"Analysis process detected!"fullword wide
$s1text"User is inactive!, give up capture"wide
$s2text"Capturing screen..."wide
$s3text"%s\\P%02d%lu.tmp"fullword wide
$s4text"CloseHandle ScreenCaptureMutex failure! %d"fullword wide
$s5text"ScreenCaptureMutex already created! %s"fullword wide
$s6text"Create ScreenCaptureMutex %s failure %d"fullword wide
$s7regex/ScreenCaptureThread\s(finished|terminated)!/wide
$s8regex/ScreenCapture_(x64|x32|Win64|Win32)_DllRelease\.dll/fullword ascii

Condition

uint16( 0 ) == 0x5a4d and ( ( all of ( $ai* ) and 1 of ( $s* ) ) or ( 3 of ( $s* ) and 1 of ( $ai* ) ) or 6 of them )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in ( $ai* ) must match.
  • At least 1 patterns in ( $s* ) must match.
  • At least 3 patterns in ( $s* ) must match.
  • At least 1 patterns in ( $ai* ) must match.
  • At least 6 patterns in the rule 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: ef0b6b88-8b1b-5ab5-ad81-276eaff0411f

Tags:FILE