YARA · SEKOIA.IO Community

SEKOIA_Apt_Kimsuky_Fpspy

Detects FPSpy, a backdoor used by Kimsuky

APT / threat actorKimsukyFpspySEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X

Author: Sekoia.io
Date: 2024-09-27
Modified: 2024-12-19
Score / Quality: 75 / 80

What this rule detects

Detects FPSpy, a backdoor used by Kimsuky

Associated malware family: Kimsuky, Fpspy.

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

apt-kimsuky-fpspy.yarDetection Rule License 1.1

rule SEKOIA_Apt_Kimsuky_Fpspy : FILE
{
	meta:
		description = "Detects FPSpy, a backdoor used by Kimsuky"
		author = "Sekoia.io"
		id = "75d41851-a7a6-4068-8ea5-6a3e6e62a965"
		date = "2024-09-27"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_kimsuky_fpspy.yar#L1-L22"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		hash = "6d6c1b175e435f5564341cc1f2c33ddf"
		hash = "54c58b72f98cb63c44e7694add551e9d"
		logic_hash = "65904b77a30b2e2a25f8d80ab32742f0ad931f07c034ae576a4fbde7e1fd999c"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$ = "Chrome/31.0." wide
		$ = "%srundll32.exe %s, %s %%1" wide
		$ = "MazeFunc" wide
		$ = "sys.dll" wide
		$ = "KLog" wide

	condition:
		uint16be( 0 ) == 0x4d5a and 4 of them
}

Strings (5 patterns)

Identifier	Type	Value	Modifiers
$	text	"Chrome/31.0."	wide
$	text	"%srundll32.exe %s, %s %%1"	wide
$	text	"MazeFunc"	wide
$	text	"sys.dll"	wide
$	text	"KLog"	wide

Condition

uint16be( 0 ) == 0x4d5a 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.

Test this rule in your browser

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References

https://github.com/SEKOIA-IO/Community

Sample hashes

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

6d6c1b175e435f5564341cc1f2c33ddf
54c58b72f98cb63c44e7694add551e9d

Licence & attribution

Author: Sekoia.io

Source repository: SEKOIA.IO Community @ a438a5901a

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: 75d41851-a7a6-4068-8ea5-6a3e6e62a965

Metadata

version	1.0
classification	TLP:CLEAR

Tags:FILE

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