YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_KE3CHANG_TMPFILE

Detects Strings left in TMP Files created by K3CHANG Backdoor Ketrican

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

Author: Markus Neis, Swisscom
Date: 2020-06-18
Modified: 2023-12-05
Score / Quality: 75 / 85

What this rule detects

Detects Strings left in TMP Files created by K3CHANG Backdoor Ketrican

Associated malware family: Ketrican.

It defines 7 patterns (7 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-ke3chang-tmpfile.yarDetection Rule License 1.1

rule SIGNATURE_BASE_APT_KE3CHANG_TMPFILE : APT KE3CHANG TMPFILE FILE
{
	meta:
		description = "Detects Strings left in TMP Files created by K3CHANG Backdoor Ketrican"
		author = "Markus Neis, Swisscom"
		id = "84d411af-ea3d-5862-8c2f-7caca60c1b66"
		date = "2020-06-18"
		modified = "2023-12-05"
		reference = "https://app.any.run/tasks/a96f4f9d-c27d-490b-b5d3-e3be0a1c93e9/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_ke3chang.yar#L1-L21"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "4ef11e84d5203c0c425d1a76d4bf579883d40577c2e781cdccc2cc4c8a8d346f"
		logic_hash = "75c97fe2eeb82e09f52e98d76bd529824f171da4c802b5febc1036314d8145f0"
		score = 75
		quality = 85
		tags = "APT, KE3CHANG, TMPFILE, FILE"

	strings:
		$pps1 = "PSParentPath             : Microsoft.PowerShell.Core\\Registry::HKEY_CURRENT_USE" fullword ascii
		$pps2 = "PSPath                   : Microsoft.PowerShell.Core\\Registry::HKEY_CURRENT_USE" fullword ascii
		$psp1 = ": Microsoft.PowerShell.Core\\Registry" ascii
		$s4 = "PSChildName  : PhishingFilter" fullword ascii
		$s1 = "DisableFirstRunCustomize : 2" fullword ascii
		$s7 = "PSChildName  : 3" fullword ascii
		$s8 = "2500         : 3" fullword ascii

	condition:
		uint16( 0 ) == 0x5350 and filesize < 1KB and $psp1 and 1 of ( $pps* ) and 1 of ( $s* )
}

Strings (7 patterns)

Identifier	Type	Value	Modifiers
$pps1	text	"PSParentPath : Microsoft.PowerShell.Core\\Registry::HKEY_CURRENT_USE"	fullword ascii
$pps2	text	"PSPath : Microsoft.PowerShell.Core\\Registry::HKEY_CURRENT_USE"	fullword ascii
$psp1	text	": Microsoft.PowerShell.Core\\Registry"	ascii
$s4	text	"PSChildName : PhishingFilter"	fullword ascii
$s1	text	"DisableFirstRunCustomize : 2"	fullword ascii
$s7	text	"PSChildName : 3"	fullword ascii
$s8	text	"2500 : 3"	fullword ascii

Condition

uint16( 0 ) == 0x5350 and filesize < 1KB and $psp1 and 1 of ( $pps* ) and 1 of ( $s* )

In plain words (Heuristic)

The file must be smaller than 1KB (a cheap guard that skips large files).
At least 1 patterns in ( $pps* ) must match.
At least 1 patterns in ( $s* ) must match.
Pattern $psp1 must be present.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

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

Open in editor

References

https://app.any.run/tasks/a96f4f9d-c27d-490b-b5d3-e3be0a1c93e9/

Sample hashes

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

4ef11e84d5203c0c425d1a76d4bf579883d40577c2e781cdccc2cc4c8a8d346f

Licence & attribution

Author: Markus Neis, Swisscom

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: 84d411af-ea3d-5862-8c2f-7caca60c1b66

Tags:APT KE3CHANG TMPFILE FILE

SIGNATURE_BASE_APT_MAL_Ke3Chang_Ketrican_Jun20_1
APT / threat actorSignature Base (Florian Roth / Nextron)· Florian Roth (Nextron Systems)· 2020-06-18
MALPEDIA_Win_Ketrican_Auto
MalwareMalpedia signator rules· Felix Bilstein - yara-signator at cocacoding dot com· 2026-05-04
SIGNATURE_BASE_APT_NK_Scarcruft_Evolved_ROKRAT
APT / threat actorSignature Base (Florian Roth / Nextron)· S2WLAB_TALON_JACK2· 2021-07-09
SIGNATURE_BASE_APT_NK_Scarcruft_RUBY_Shellcode_XOR_Routine
APT / threat actorSignature Base (Florian Roth / Nextron)· S2WLAB_TALON_JACK2· 2021-05-20
SIGNATURE_BASE_APT_WEBSHELL_HAFNIUM_Chopper_Webshell
APT / threat actorSignature Base (Florian Roth / Nextron)· Markus Neis,Swisscom· 2021-03-05
SIGNATURE_BASE_APT_WEBSHELL_Tiny_Webshell
APT / threat actorSignature Base (Florian Roth / Nextron)· Markus Neis,Swisscom· 2021-03-05

More Ketrican rules