YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_CN_MAL_Reddelta_Shellcode_Loader_Oct20_2

Detects Red Delta samples

APT / threat actorSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X

Author: Florian Roth (Nextron Systems)
Date: 2020-10-14
Modified: 2023-12-05
Score / Quality: 75 / 85

What this rule detects

Detects Red Delta samples

Targets: Windows PE.

It defines 9 patterns (8 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-cn-mal-reddelta-shellcode-loader-oct20-2.yarDetection Rule License 1.1

rule SIGNATURE_BASE_APT_CN_MAL_Reddelta_Shellcode_Loader_Oct20_2 : FILE
{
	meta:
		description = "Detects Red Delta samples"
		author = "Florian Roth (Nextron Systems)"
		id = "acb1024a-64af-51ac-84c8-7fe9a5bd4538"
		date = "2020-10-14"
		modified = "2023-12-05"
		reference = "https://twitter.com/JAMESWT_MHT/status/1316387482708119556"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_cn_reddelta.yar#L31-L57"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "260ebbf392498d00d767a5c5ba695e1a124057c1c01fff2ae76db7853fe4255b"
		hash = "9ccb4ed133be5c9c554027347ad8b722f0b4c3f14bfd947edfe75a015bf085e5"
		hash = "b3fd750484fca838813e814db7d6491fea36abe889787fb7cf3fb29d9d9f5429"
		logic_hash = "179265c0b2175bc3d2d581a69e50e9b8b9cc918a6fdc7bcef42fb163c49b077a"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$x1 = "\\CLRLoader.exe" wide fullword
		$x2 = "/callback.php?token=%s&computername=%s&username=%s" ascii fullword
		$s1 = "DotNetLoader.Program" wide fullword
		$s2 = "/download.php?api=40" ascii fullword
		$s3 = "get %d URLDir" ascii fullword
		$s4 = "Read code failed" ascii fullword
		$s5 = "OpenFile fail!" wide fullword
		$s6 = "Writefile success" wide fullword
		$op1 = { 4c 8d 45 e0 49 8b cc 41 8d 51 c3 e8 34 77 02 00 }

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 3000KB and 1 of ( $x* ) or 4 of them
}

Strings (9 patterns)

Identifier	Type	Value	Modifiers
$x1	text	"\\CLRLoader.exe"	wide fullword
$x2	text	"/callback.php?token=%s&computername=%s&username=%s"	ascii fullword
$s1	text	"DotNetLoader.Program"	wide fullword
$s2	text	"/download.php?api=40"	ascii fullword
$s3	text	"get %d URLDir"	ascii fullword
$s4	text	"Read code failed"	ascii fullword
$s5	text	"OpenFile fail!"	wide fullword
$s6	text	"Writefile success"	wide fullword
$op1	hex	{ 4c 8d 45 e0 49 8b cc 41 8d 51 c3 e8 34 77 02 00 }

Condition

uint16( 0 ) == 0x5a4d and filesize < 3000KB and 1 of ( $x* ) or 4 of them

In plain words (Heuristic)

The file must start with “MZ” — a Windows executable (PE).
The file must be smaller than 3000KB (a cheap guard that skips large files).
At least 1 patterns in ( $x* ) must match.
At least 4 patterns in the rule must match.

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References

https://twitter.com/JAMESWT_MHT/status/1316387482708119556

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

260ebbf392498d00d767a5c5ba695e1a124057c1c01fff2ae76db7853fe4255b
9ccb4ed133be5c9c554027347ad8b722f0b4c3f14bfd947edfe75a015bf085e5
b3fd750484fca838813e814db7d6491fea36abe889787fb7cf3fb29d9d9f5429

Licence & attribution

Author: Florian Roth (Nextron Systems)

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

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

Rule id: acb1024a-64af-51ac-84c8-7fe9a5bd4538

Tags:FILE

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