YARA · SEKOIA.IO Community

SEKOIA_Apt_Toddycat_Waexp_Strings

Detects WAExp based on strings

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

Author: Sekoia.io
Date: 2024-04-23
Modified: 2024-12-19
Score / Quality: 75 / 80

What this rule detects

Detects WAExp based on strings

Targets: Windows PE, Linux ELF.

It defines 3 patterns (3 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-toddycat-waexp-strings.yarDetection Rule License 1.1

rule SEKOIA_Apt_Toddycat_Waexp_Strings : FILE
{
	meta:
		description = "Detects WAExp based on strings"
		author = "Sekoia.io"
		id = "1bbb3e81-14a9-4bda-b647-b6f5255e9a16"
		date = "2024-04-23"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_toddycat_waexp_strings.yar#L1-L18"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "4377183b326329fb14ae3911fbb1e29cde220d7b247d048fba4bbbda9de8938d"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$ = "[>] Profile:" wide ascii
		$ = "[+] All Done" wide ascii
		$ = "[+] Files:" wide ascii

	condition:
		( uint32be( 0 ) == 0x7f454c46 or uint16be( 0 ) == 0x4d5a ) and all of them and filesize < 1MB
}

Strings (3 patterns)

Identifier	Type	Value	Modifiers
$	text	"[>] Profile:"	wide ascii
$	text	"[+] All Done"	wide ascii
$	text	"[+] Files:"	wide ascii

Condition

( uint32be( 0 ) == 0x7f454c46 or uint16be( 0 ) == 0x4d5a ) and all of them and filesize < 1MB

In plain words (Heuristic)

The file must start with “MZ” — a Windows executable (PE).
The file must start with the ELF header — a Linux/Unix executable.
The file must be smaller than 1MB (a cheap guard that skips large files).
All patterns in the rule must match.

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References

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

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: 1bbb3e81-14a9-4bda-b647-b6f5255e9a16

Metadata

version	1.0
classification	TLP:CLEAR

Tags:FILE

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