YARA · SEKOIA.IO Community

SEKOIA_Apt_Apt31_Pakdoor

Detects APT31 ORB implant - 2019/2021

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

Author: Sekoia.io
Date: 2021-10-11
Modified: 2024-12-19
Score / Quality: 75 / 80

What this rule detects

Detects APT31 ORB implant - 2019/2021

It defines 5 patterns (4 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-apt31-pakdoor.yarDetection Rule License 1.1

rule SEKOIA_Apt_Apt31_Pakdoor : FILE
{
	meta:
		description = "Detects APT31 ORB implant - 2019/2021"
		author = "Sekoia.io"
		id = "463b8d0d-30f4-45ed-8f19-4b32436fbbf0"
		date = "2021-10-11"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_apt31_pakdoor.yar#L1-L25"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		hash = "1d60edb577641ce47dc2a8299f8b7f878e37120b192655aaf80d1cde5ee482d2"
		logic_hash = "ef001e31b34761688f32ec767082d9d7f9fc4e4368d567eb64b66583bcb7fc78"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"
		version = "1.0"

	strings:
		$s1 = "mv -f %s %s ;chmod 777 %s"
		$s2 = "GET /plain HTTP/1.1"
		$s3 = "exc_cmd time out"
		$s4 = "exc_cmd pipe err"
		$s5 = { 2e 2f [1-10] 20 20 64 65 6c }

	condition:
		int32be ( 0 ) == 0x7f454c46 and filesize < 800KB and filesize > 400KB and 4 of ( $s* )
}

Strings (5 patterns)

Identifier	Type	Value
$s1	text	"mv -f %s %s ;chmod 777 %s"
$s2	text	"GET /plain HTTP/1.1"
$s3	text	"exc_cmd time out"
$s4	text	"exc_cmd pipe err"
$s5	hex	{ 2e 2f [1-10] 20 20 64 65 6c }

Condition

int32be ( 0 ) == 0x7f454c46 and filesize < 800KB and filesize > 400KB and 4 of ( $s* )

In plain words (Heuristic)

The file must be smaller than 800KB (a cheap guard that skips large files).
The file must be larger than 400KB.
At least 4 patterns in ( $s* ) must match.

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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).

1d60edb577641ce47dc2a8299f8b7f878e37120b192655aaf80d1cde5ee482d2

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: 463b8d0d-30f4-45ed-8f19-4b32436fbbf0

Metadata

version	1.0
classification	TLP:CLEAR
version	1.0

Tags:FILE

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