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SEKOIA_Downloader_Win_Cobianrat

Detect CobianRAT downloader

MalwareCobianratSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2024-08-23
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detect CobianRAT downloader

Associated malware family: Cobianrat.

Targets: Windows PE.

It defines 1 patterns (0 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
downloader-win-cobianrat.yarDetection Rule License 1.1
rule SEKOIA_Downloader_Win_Cobianrat : FILE
{
	meta:
		description = "Detect CobianRAT downloader"
		author = "Sekoia.io"
		id = "7a86c17f-bf4e-4465-9488-244b75fc36f1"
		date = "2024-08-23"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/downloader_win_cobianrat.yar#L1-L23"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		hash = "7a70779d9d7de5e370fac0fa2d4ccd13"
		hash = "2ce40599a4990680db3af5defcd5381a"
		hash = "56515c48f82475e7bb6a26b027a459d7"
		hash = "3450bece12bd8103d5e718a2661d0404"
		hash = "132858739129d2b863dc547facbed7e9"
		hash = "693bd96d162c54d7e9605580eaf54a6e"
		hash = "d03a4988e22e6c7b2a03efa2bdb1502d"
		hash = "ab8c68b907ec2ce316bf18f00938710c"
		logic_hash = "6437a2d0854fb7bd9ddde8434e9a2b95cbb7ccc04381400db211f38a6a575e43"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$ = {24 00 44 00 6F 00 77 00 6E 00 6C 00 6F 00 61 00 64 00 55 00 72 00 6C 00 20 00 3D 00 20 00 27}

	condition:
		uint16be( 0 ) == 0x4d5a and all of them
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$hex{24 00 44 00 6F 00 77 00 6E 00 6C 00 6F 00 61 00 64 00 55 00 72 00 6C 00 20 00 3D 00 20 00 27}

Condition

uint16be( 0 ) == 0x4d5a and all of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in the rule must match.

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References

Sample hashes

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

  • 7a70779d9d7de5e370fac0fa2d4ccd13
  • 2ce40599a4990680db3af5defcd5381a
  • 56515c48f82475e7bb6a26b027a459d7
  • 3450bece12bd8103d5e718a2661d0404
  • 132858739129d2b863dc547facbed7e9
  • 693bd96d162c54d7e9605580eaf54a6e
  • d03a4988e22e6c7b2a03efa2bdb1502d
  • ab8c68b907ec2ce316bf18f00938710c

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: 7a86c17f-bf4e-4465-9488-244b75fc36f1

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE

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