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YARA · ditekSHen detection

DITEKSHEN_MALWARE_Win_Caspertroy

Detects CasperTroy payload

MalwareCaspertroyditekSHen 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 CasperTroy payload

Associated malware family: Caspertroy.

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
malware-win-caspertroy.yarBSD 2-Clause License
rule DITEKSHEN_MALWARE_Win_Caspertroy : FILE
{
	meta:
		description = "Detects CasperTroy payload"
		author = "ditekSHen"
		id = "822c3231-60ba-5e60-8df8-06dea80b318a"
		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#L2919-L2931"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "ce070b1e6279ef9fa47f84da7c5166cd93b3e7a0f95541ae14c048b2af9bc431"
		score = 75
		quality = 75
		tags = "FILE"

	strings:
		$s1 = "DllTroy.dll" fullword ascii
		$s2 = "Content-Disposition: form-data; name=\"image\"; filename=\"title.gif\"" fullword ascii
		$s3 = "Content-Disposition: form-data; name=\"COOKIE_ID\"" fullword ascii
		$s4 = "Content-Disposition: form-data; name=\"PHP_SESS_ID\"" fullword ascii
		$s5 = "Content-Disposition: form-data; name=\"SESS_ID\"" fullword ascii

	condition:
		uint16( 0 ) == 0x5a4d and 4 of them
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$s1text"DllTroy.dll"fullword ascii
$s2text"Content-Disposition: form-data; name=\"image\"; filename=\"title.gif\""fullword ascii
$s3text"Content-Disposition: form-data; name=\"COOKIE_ID\""fullword ascii
$s4text"Content-Disposition: form-data; name=\"PHP_SESS_ID\""fullword ascii
$s5text"Content-Disposition: form-data; name=\"SESS_ID\""fullword ascii

Condition

uint16( 0 ) == 0x5a4d and 4 of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least 4 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: 822c3231-60ba-5e60-8df8-06dea80b318a

Tags:FILE

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