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SEKOIA_Rat_Win_Asyncrat

Detect AsyncRAT based on specific strings

MalwareSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2023-01-25
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detect AsyncRAT based on specific strings

Targets: Windows PE.

It defines 12 patterns (12 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

rat-win-asyncrat.yarDetection Rule License 1.1
rule SEKOIA_Rat_Win_Asyncrat : FILE
{
	meta:
		description = "Detect AsyncRAT based on specific strings"
		author = "Sekoia.io"
		id = "d698e4a1-77ff-4cd7-acb3-27fb16168ceb"
		date = "2023-01-25"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/rat_win_asyncrat.yar#L1-L26"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "5e35b034ba1761fae780429be377b70ae8ce62273670042ff067c38ed8bb5a9e"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$str01 = "get_ActivatePong" ascii
		$str02 = "get_SslClient" ascii
		$str03 = "get_TcpClient" ascii
		$str04 = "get_SendSync" ascii
		$str05 = "get_IsConnected" ascii
		$str06 = "set_UseShellExecute" ascii
		$str07 = "Pastebin" wide
		$str08 = "Select * from AntivirusProduct" wide
		$str09 = "Stub.exe" wide
		$str10 = "timeout 3 > NUL" wide
		$str11 = "/c schtasks /create /f /sc onlogon /rl highest /tn " wide
		$str12 = "\\nuR\\noisreVtnerruC\\swodniW\\tfosorciM\\erawtfoS" wide

	condition:
		uint16( 0 ) == 0x5A4D and 9 of them
}

Strings (12 patterns)

IdentifierTypeValueModifiers
$str01text"get_ActivatePong"ascii
$str02text"get_SslClient"ascii
$str03text"get_TcpClient"ascii
$str04text"get_SendSync"ascii
$str05text"get_IsConnected"ascii
$str06text"set_UseShellExecute"ascii
$str07text"Pastebin"wide
$str08text"Select * from AntivirusProduct"wide
$str09text"Stub.exe"wide
$str10text"timeout 3 > NUL"wide
$str11text"/c schtasks /create /f /sc onlogon /rl highest /tn "wide
$str12text"\\nuR\\noisreVtnerruC\\swodniW\\tfosorciM\\erawtfoS"wide

Condition

uint16( 0 ) == 0x5A4D and 9 of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least 9 patterns in the rule must match.

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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: d698e4a1-77ff-4cd7-acb3-27fb16168ceb

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE