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SEKOIA_Loader_Win_Squirrelwaffle_Doc

Detect the Squirrelwaffle malicious document (not xls)

MalwareSquirrelwaffleSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X (with warnings)
Author
Sekoia.io
Date
2021-09-20
Modified
2024-12-19
Score / Quality
75 / 76

What this rule detects

Detect the Squirrelwaffle malicious document (not xls)

Associated malware family: Squirrelwaffle.

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

YARA-X says: warning[text_as_hex]: hex pattern could be written as text literal

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
loader-win-squirrelwaffle-doc.yarDetection Rule License 1.1
rule SEKOIA_Loader_Win_Squirrelwaffle_Doc : FILE
{
	meta:
		description = "Detect the Squirrelwaffle malicious document (not xls)"
		author = "Sekoia.io"
		id = "caadeac3-d4c7-4d84-b539-c03cc4c6c274"
		date = "2021-09-20"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/loader_win_squirrelwaffle_doc.yar#L1-L18"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "b9f7c3605e25c8c7caa5f70e492d46fb70e7cb6002704440e7346ebfb2bbc7bf"
		score = 75
		quality = 76
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$s1 = {4f4b31203d2022636d64202f632072756e646c6c33322e65786520433a5c50726f6772616d446174615c777777312e646c6c2c6c647222}
		$s2 = {4145524f2042495a20434f4d20434f4f502045445520474f5620494e464f20494e54204d494c204d555345554d204e414d45204e4554204f52472050524f}

	condition:
		any of them and filesize > 100KB
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$s1hex{4f4b31203d2022636d64202f632072756e646c6c33322e65786520433a5c50726f6772616d446174615c777777312e646c6c2c6c647222}
$s2hex{4145524f2042495a20434f4d20434f4f502045445520474f5620494e464f20494e54204d494c204d555345554d204e414d45204e4554204f52472050524f}

Condition

any of them and filesize > 100KB

In plain words (Heuristic)

  • The file must be larger than 100KB.
  • At least one pattern in the rule must match.

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References

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: caadeac3-d4c7-4d84-b539-c03cc4c6c274

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE

Related rules

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