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WITHSECURELABS_Andariel_Undercrypt_Versioninfo

Detects UnderCrypt samples based on version info

GenericWithSecure Labs IOCsBSD 2-Clause LicenseCompiles with YARA-X
Author
WithSecure
Date
2026-01-22
Score / Quality
75 / 75

What this rule detects

Detects UnderCrypt samples based on version info

It has no patterns: the condition alone decides (modules, file properties or other rules). YARA modules used: pe.

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

Includes the imports needed to compile it on its own.

andariel-undercrypt-versioninfo.yarBSD 2-Clause License
import "pe"

rule WITHSECURELABS_Andariel_Undercrypt_Versioninfo
{
	meta:
		description = "Detects UnderCrypt samples based on version info"
		author = "WithSecure"
		id = "03ed3929-12e9-5a8f-bdef-394396679a19"
		date = "2026-01-22"
		modified = "2026-01-22"
		reference = "https://github.com/WithSecureLabs/iocs"
		source_url = "https://github.com/WithSecureLabs/iocs/blob/1a8384468dd292c6d2c5114c32e42dc0da1f5ae1/Andariel2025/andariel.yara#L54-L67"
		license_url = "https://github.com/WithSecureLabs/iocs/blob/1a8384468dd292c6d2c5114c32e42dc0da1f5ae1/LICENSE"
		logic_hash = "2d87246f89128a97136c021653211109d44dc9c75be747e58c7d09ebdac092ed"
		score = 75
		quality = 75
		tags = ""

	condition:
		(pe.version_info [ "ProductName" ] == "Microsoft@Windows@OperatingSystem" ) or ( pe.version_info [ "InternalName" ] contains "_crypted." and pe.version_info [ "FileVersion" ] contains "10.0.19041.1" )
}

Condition

(pe.version_info [ "ProductName" ] == "Microsoft@Windows@OperatingSystem" ) or ( pe.version_info [ "InternalName" ] contains "_crypted." and pe.version_info [ "FileVersion" ] contains "10.0.19041.1" )

In plain words (Heuristic)

  • Uses the pe module.

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References

Licence & attribution

Author: WithSecure

Source repository: WithSecure Labs IOCs @ 1a8384468d

Licence: BSD 2-Clause License (repository licence)

Copyright notice: Copyright (c) 2022, WithSecure Oyj

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: 03ed3929-12e9-5a8f-bdef-394396679a19

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