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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_LNX_Camarodragon_Horseshell_Oct23

Detects CamaroDragon's HorseShell implant for routers

MalwareSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth
Date
2023-10-06
Modified
2023-12-05
Score / Quality
85 / 85

What this rule detects

Detects CamaroDragon's HorseShell implant for routers

It defines 10 patterns (8 text, 2 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-lnx-camarodragon-horseshell-oct23.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_LNX_Camarodragon_Horseshell_Oct23 : FILE
{
	meta:
		description = "Detects CamaroDragon's HorseShell implant for routers"
		author = "Florian Roth"
		id = "9e54745f-146f-50a6-b30f-53aaaa6907b5"
		date = "2023-10-06"
		modified = "2023-12-05"
		reference = "https://research.checkpoint.com/2023/the-dragon-who-sold-his-camaro-analyzing-custom-router-implant/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_camaro_dragon_oct23.yar#L27-L56"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "998788472cb1502c03675a15a9f09b12f3877a5aeb687f891458a414b8e0d66c"
		logic_hash = "73adaa286b345cffd35e6ba017b3204d8818dcaeea8a48ca93959566461ac3ca"
		score = 85
		quality = 85
		tags = "FILE"

	strings:
		$x1 = "echo \"start shell '%s' failed!\" > .remote_shell.log" ascii fullword
		$x2 = "*****recv NET_REQ_HORSE_SHELL REQ_CONNECT_PORT*****" ascii fullword
		$s1 = "m.cremessage.com" ascii fullword
		$s2 = "POST http://%s/index.php HTTP/1.1" ascii fullword
		$s3 = "wzsw_encrypt_buf" ascii fullword
		$s4 = "body:%d-%s" ascii fullword
		$s5 = "User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident" ascii fullword
		$s6 = "process_http_read_events" ascii fullword
		$op1 = { c4 34 42 00 02 30 63 00 40 10 60 00 09 ae 62 00 48 8e 62 00 cc }
		$op2 = { 27 f4 8c 46 27 f0 03 20 f8 09 00 60 28 21 }

	condition:
		uint16( 0 ) == 0x457f and filesize < 600KB and ( 1 of ( $x* ) or 3 of them ) or 5 of them
}

Strings (10 patterns)

IdentifierTypeValueModifiers
$x1text"echo \"start shell '%s' failed!\" > .remote_shell.log"ascii fullword
$x2text"*****recv NET_REQ_HORSE_SHELL REQ_CONNECT_PORT*****"ascii fullword
$s1text"m.cremessage.com"ascii fullword
$s2text"POST http://%s/index.php HTTP/1.1"ascii fullword
$s3text"wzsw_encrypt_buf"ascii fullword
$s4text"body:%d-%s"ascii fullword
$s5text"User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident"ascii fullword
$s6text"process_http_read_events"ascii fullword
$op1hex{ c4 34 42 00 02 30 63 00 40 10 60 00 09 ae 62 00 48 8e 62 00 cc }
$op2hex{ 27 f4 8c 46 27 f0 03 20 f8 09 00 60 28 21 }

Condition

uint16( 0 ) == 0x457f and filesize < 600KB and ( 1 of ( $x* ) or 3 of them ) or 5 of them

In plain words (Heuristic)

  • The file must be smaller than 600KB (a cheap guard that skips large files).
  • At least 1 patterns in ( $x* ) must match.
  • At least 3 patterns in the rule must match.
  • At least 5 patterns in the rule must match.

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References

Sample hashes

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

  • 998788472cb1502c03675a15a9f09b12f3877a5aeb687f891458a414b8e0d66c

Licence & attribution

Author: Florian Roth

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: 9e54745f-146f-50a6-b30f-53aaaa6907b5

Tags:FILE

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