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ESET_Apt_Windows_Invisimole_DNS_Downloader

InvisiMole DNS downloader

APT / threat actorInvisimoleESET malware-iocBSD 2-Clause LicenseCompiles with YARA-X
Author
ESET Research
Date
2021-05-17
Score / Quality
75 / 80

What this rule detects

InvisiMole DNS downloader

Associated malware family: Invisimole.

Targets: Windows PE.

It defines 14 patterns (14 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Includes the imports and 1 rule(s) it depends on needed to compile it on its own.

apt-windows-invisimole-dns-downloader.yarBSD 2-Clause License
private rule ESET_Invisimole_Blob_PRIVATE
{
	meta:
		description = "Detects InvisiMole blobs by magic values"
		author = "ESET Research"
		id = "6a179d91-50f1-5400-b141-0f162efd2431"
		date = "2021-05-17"
		modified = "2021-05-17"
		reference = "https://github.com/eset/malware-ioc/"
		source_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/invisimole/invisimole.yar#L34-L52"
		license_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/LICENSE"
		logic_hash = "8bddaf874da58fbe6362498f8979b511f39531fe2b98d4be8c099bdafb6d0067"
		score = 75
		quality = 80
		tags = ""
		license = "BSD 2-Clause"
		version = "1"

	strings:
		$magic_old_32 = {F9 FF D0 DE}
		$magic_old_64 = {64 FF D0 DE}
		$magic_new_32 = {86 DA 11 CE}
		$magic_new_64 = {64 DA 11 CE}

	condition:
		($magic_old_32 at 0 ) or ( $magic_old_64 at 0 ) or ( $magic_new_32 at 0 ) or ( $magic_new_64 at 0 )
}

rule ESET_Apt_Windows_Invisimole_DNS_Downloader : FILE
{
	meta:
		description = "InvisiMole DNS downloader"
		author = "ESET Research"
		id = "1caa6c8b-3798-556e-835e-885b7f3f4511"
		date = "2021-05-17"
		modified = "2021-05-17"
		reference = "https://github.com/eset/malware-ioc/"
		source_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/invisimole/invisimole.yar#L140-L170"
		license_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/LICENSE"
		logic_hash = "88d6ed7ec1331153d19afc18473a4be2b214ad8af29fcf7051a2a8e40e088231"
		score = 75
		quality = 80
		tags = "FILE"
		license = "BSD 2-Clause"
		version = "1"

	strings:
		$d = "DnsQuery_A"
		$s1 = "Wireshark-is-running-{9CA78EEA-EA4D-4490-9240-FC01FCEF464B}" xor
		$s2 = "AddIns\\" ascii wide xor
		$s3 = "pcornomeex." xor
		$s4 = "weriahsek.rxe" xor
		$s5 = "dpmupaceex." xor
		$s6 = "TCPViewClass" xor
		$s7 = "PROCMON_WINDOW_CLASS" xor
		$s8 = "Key%C"
		$s9 = "AutoEx%C" xor
		$s10 = "MSO~"
		$s11 = "MDE~"
		$s12 = "DNS PLUGIN, Step %d" xor
		$s13 = "rundll32.exe \"%s\",StartUI"

	condition:
		(( uint16( 0 ) == 0x5A4D ) or ESET_Invisimole_Blob_PRIVATE ) and $d and 5 of ( $s* )
}

Strings (14 patterns)

IdentifierTypeValueModifiers
$dtext"DnsQuery_A"
$s1text"Wireshark-is-running-{9CA78EEA-EA4D-4490-9240-FC01FCEF464B}"xor
$s2text"AddIns\\"ascii wide xor
$s3text"pcornomeex."xor
$s4text"weriahsek.rxe"xor
$s5text"dpmupaceex."xor
$s6text"TCPViewClass"xor
$s7text"PROCMON_WINDOW_CLASS"xor
$s8text"Key%C"
$s9text"AutoEx%C"xor
$s10text"MSO~"
$s11text"MDE~"
$s12text"DNS PLUGIN, Step %d"xor
$s13text"rundll32.exe \"%s\",StartUI"

Condition

(( uint16( 0 ) == 0x5A4D ) or ESET_Invisimole_Blob_PRIVATE ) and $d and 5 of ( $s* )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least 5 patterns in ( $s* ) must match.
  • Depends on the rule ESET_Invisimole_Blob_PRIVATE.
  • Pattern $d must be present.

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References

Licence & attribution

Author: ESET Research

Source repository: ESET malware-ioc @ 17baf44964

Licence: BSD 2-Clause License (stated in the rule's own meta)

“BSD 2-Clause”

Copyright notice: Copyright (c) 2014-2018 ESET spol. s r.o.

Original rule

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

Rule id: 1caa6c8b-3798-556e-835e-885b7f3f4511

Metadata

version1

Tags:FILE

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