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SEKOIA_Infostealer_Win_Solarmarker_Dll

Finds SolarMarker DLL based on characteristic strings

MalwareSolarmarkerSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2022-12-09
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Finds SolarMarker DLL based on characteristic strings

Associated malware family: Solarmarker.

Targets: Windows PE.

It defines 11 patterns (11 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

infostealer-win-solarmarker-dll.yarDetection Rule License 1.1
rule SEKOIA_Infostealer_Win_Solarmarker_Dll : FILE
{
	meta:
		description = "Finds SolarMarker DLL based on characteristic strings"
		author = "Sekoia.io"
		id = "a2fe7f09-7134-4054-ba40-5ea66785a26c"
		date = "2022-12-09"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/infostealer_win_solarmarker_dll.yar#L1-L28"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "5be0a95adb7e486cdec5f0e8433afed41516fc1a990e1d1ba00db7e8fb32dbbb"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$zka = "zkabsr" wide
		$str0 = "set_PersistKeyInCsp" ascii
		$str1 = "get_IV" ascii
		$str2 = "get_MachineName" ascii
		$str3 = "get_Current" ascii
		$str4 = "ps_script" ascii
		$str5 = "request_data" ascii
		$str6 = "WindowsBuiltInRole" ascii
		$str7 = "DllImportAttribute" ascii
		$str8 = "get_BlockSize" ascii
		$str9 = "GetRequestStream" ascii

	condition:
		uint16( 0 ) == 0x5A4D and ( ( $zka and 3 of ( $str* ) ) or ( all of ( $str* ) ) ) and filesize < 1MB
}

Strings (11 patterns)

IdentifierTypeValueModifiers
$zkatext"zkabsr"wide
$str0text"set_PersistKeyInCsp"ascii
$str1text"get_IV"ascii
$str2text"get_MachineName"ascii
$str3text"get_Current"ascii
$str4text"ps_script"ascii
$str5text"request_data"ascii
$str6text"WindowsBuiltInRole"ascii
$str7text"DllImportAttribute"ascii
$str8text"get_BlockSize"ascii
$str9text"GetRequestStream"ascii

Condition

uint16( 0 ) == 0x5A4D and ( ( $zka and 3 of ( $str* ) ) or ( all of ( $str* ) ) ) and filesize < 1MB

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 1MB (a cheap guard that skips large files).
  • All patterns in ( $str* ) must match.
  • At least 3 patterns in ( $str* ) must match.
  • Pattern $zka must be present.

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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: a2fe7f09-7134-4054-ba40-5ea66785a26c

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE

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