Skip to content

YARA · SEKOIA.IO Community

SEKOIA_Malware_Valleyrat_Strings_Config

ValleyRAT strings based on HIVE KEYS and config.

MalwareSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2024-08-19
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

ValleyRAT strings based on HIVE KEYS and config.

Targets: Windows PE.

It defines 5 patterns (3 text, 2 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

malware-valleyrat-strings-config.yarDetection Rule License 1.1
rule SEKOIA_Malware_Valleyrat_Strings_Config : FILE
{
	meta:
		description = "ValleyRAT strings based on HIVE KEYS and config. "
		author = "Sekoia.io"
		id = "bb186ab7-60cd-487e-8b9c-c2ff8f121454"
		date = "2024-08-19"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/malware_valleyrat_strings_config.yar#L1-L27"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		hash = "b1887a48e59ac7b1b1742854d2a228af"
		hash = "f6c69e83ce61aacacfbc410345008268"
		hash = "63ad42e03aca6ce447fb447e21aeb385"
		hash = "e1d41e5fdfebf8062911ef3c3853b807"
		hash = "e6cafb4136a9438227086a5826eafe10"
		hash = "54ba4bbeacd1521164a40e92262b15f6"
		logic_hash = "89a3d3ca32f9c57e932686f0ed03821350770f82e598948ed86414e231e27a30"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$key1 = "IpDateInfo" ascii fullword
		$key2 = "IpDate" ascii fullword
		$key3 = "SelfPath" ascii fullword
		$config1 = {7c 00 69 00 3a 00 }
		$config2 = {7c 00 70 00 3a 00 }

	condition:
		uint16be( 0 ) == 0x4d5a and 1 of ( $key* ) and $config2 in ( @config1 .. @config1 + 100 ) and filesize > 300KB and filesize < 100MB
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$key1text"IpDateInfo"ascii fullword
$key2text"IpDate"ascii fullword
$key3text"SelfPath"ascii fullword
$config1hex{7c 00 69 00 3a 00 }
$config2hex{7c 00 70 00 3a 00 }

Condition

uint16be( 0 ) == 0x4d5a and 1 of ( $key* ) and $config2 in ( @config1 .. @config1 + 100 ) and filesize > 300KB and filesize < 100MB

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 100MB (a cheap guard that skips large files).
  • The file must be larger than 300KB.
  • At least 1 patterns in ( $key* ) must match.
  • Pattern $config2 must be found within the range @config1 .. @config1 + 100.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

Open in editor

References

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • b1887a48e59ac7b1b1742854d2a228af
  • f6c69e83ce61aacacfbc410345008268
  • 63ad42e03aca6ce447fb447e21aeb385
  • e1d41e5fdfebf8062911ef3c3853b807
  • e6cafb4136a9438227086a5826eafe10
  • 54ba4bbeacd1521164a40e92262b15f6

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: bb186ab7-60cd-487e-8b9c-c2ff8f121454

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE