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DITEKSHEN_MALWARE_Win_Akira

Detects Akira Ransomware Windows

MalwareAkiraditekSHen detectionBSD 2-Clause LicenseCompiles with YARA-X
Author
ditekSHen
Date
2020-11-06
Modified
2024-11-01
Score / Quality
75 / 75

What this rule detects

Detects Akira Ransomware Windows

Associated malware family: Akira.

Targets: Windows PE.

It defines 16 patterns (14 text, 1 hex, 1 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
malware-win-akira.yarBSD 2-Clause License
rule DITEKSHEN_MALWARE_Win_Akira : FILE
{
	meta:
		description = "Detects Akira Ransomware Windows"
		author = "ditekSHen"
		id = "350ecf81-7926-5cd2-b0c8-2dd748775e74"
		date = "2020-11-06"
		modified = "2024-11-01"
		reference = "https://github.com/ditekshen/detection"
		source_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/yara/malware.yar#L10220-L10243"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "73dd0a1b21be8ff7362536f6b6255cd19510632782effd67a56d7656bebf04ff"
		score = 75
		quality = 75
		tags = "FILE"

	strings:
		$x1 = "https://akira" ascii
		$x2 = ":\\akira\\" ascii
		$x3 = ".akira" ascii
		$x4 = "akira_readme.txt" ascii
		$x5 = "\\akira\\asio\\include\\asio\\impl\\co_spawn.hpp" ascii
		$s1 = "Get-WmiObject Win32_Shadowcopy | Remove-WmiObject" ascii
		$s2 = "Win32_ProcessStartup" fullword wide
		$s3 = /Failed\sto\smake\s(part|full|spot)\sencrypt/ ascii wide
		$s4 = "--encryption_" ascii
		$s5 = "--share_file" ascii
		$s6 = { 24 00 52 00 45 00 43 00 59 00 43 00 4C 00 45 00 2E 00 42 00 49 00 4E 00 00 00 00 00 6? 6? 6? 00 (24|57) 00 (52|69) 00 }
		$s7 = " PUBLIC KEY-----" ascii
		$s8 = ".onion" ascii
		$s9 = "/Esxi_Build_Esxi6/./" ascii nocase
		$s10 = "No path to encrypt" ascii
		$s11 = "-fork" fullword ascii

	condition:
		uint16( 0 ) == 0x5a4d and ( 3 of ( $x* ) or ( 1 of ( $x* ) and 4 of ( $s* ) ) or 6 of ( $s* ) )
}

Strings (16 patterns)

IdentifierTypeValueModifiers
$x1text"https://akira"ascii
$x2text":\\akira\\"ascii
$x3text".akira"ascii
$x4text"akira_readme.txt"ascii
$x5text"\\akira\\asio\\include\\asio\\impl\\co_spawn.hpp"ascii
$s1text"Get-WmiObject Win32_Shadowcopy | Remove-WmiObject"ascii
$s2text"Win32_ProcessStartup"fullword wide
$s3regex/Failed\sto\smake\s(part|full|spot)\sencrypt/ascii wide
$s4text"--encryption_"ascii
$s5text"--share_file"ascii
$s6hex{ 24 00 52 00 45 00 43 00 59 00 43 00 4C 00 45 00 2E 00 42 00 49 00 4E 00 00 00 00 00 6? 6? 6? 00 (24|57) 00 (52|69) 00 }
$s7text" PUBLIC KEY-----"ascii
$s8text".onion"ascii
$s9text"/Esxi_Build_Esxi6/./"ascii nocase
$s10text"No path to encrypt"ascii
$s11text"-fork"fullword ascii

Condition

uint16( 0 ) == 0x5a4d and ( 3 of ( $x* ) or ( 1 of ( $x* ) and 4 of ( $s* ) ) or 6 of ( $s* ) )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least 3 patterns in ( $x* ) must match.
  • At least 1 patterns in ( $x* ) must match.
  • At least 4 patterns in ( $s* ) must match.
  • At least 6 patterns in ( $s* ) must match.

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References

Licence & attribution

Author: ditekSHen

Source repository: ditekSHen detection @ e76c93dcde

Licence: BSD 2-Clause License (repository licence)

Copyright notice: Copyright 2021 by ditekSHen (https://github.com/ditekshen/detection).

Original rule

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

Rule id: 350ecf81-7926-5cd2-b0c8-2dd748775e74

Tags:FILE

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