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YARA · SEKOIA.IO Community

SEKOIA_Ransomware_Win_Karma

Detect the Karma ransomware payload

MalwareKarmaSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2021-08-25
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detect the Karma ransomware payload

Associated malware family: Karma.

Targets: Windows PE.

It defines 6 patterns (6 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

ransomware-win-karma.yarDetection Rule License 1.1
rule SEKOIA_Ransomware_Win_Karma : FILE
{
	meta:
		description = "Detect the Karma ransomware payload"
		author = "Sekoia.io"
		id = "efd87a17-7c99-404a-8ea6-2f5c2121f9f2"
		date = "2021-08-25"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/ransomware_win_karma.yar#L1-L21"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "ef272be7ae5fea084120db95f7b002e9061d72442836e836ca43ddc7b461be4e"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$a1 = "KARMA" ascii
		$u1 = "KARMA" wide
		$u2 = "-ENCRYPTED.txt" wide
		$u3 = "Encrypting directory:" wide
		$u4 = "Encrypting file:" wide
		$u5 = "Trying to import ECC public key..." wide

	condition:
		uint16( 0 ) == 0x5A4D and filesize < 150KB and all of them
}

Strings (6 patterns)

IdentifierTypeValueModifiers
$a1text"KARMA"ascii
$u1text"KARMA"wide
$u2text"-ENCRYPTED.txt"wide
$u3text"Encrypting directory:"wide
$u4text"Encrypting file:"wide
$u5text"Trying to import ECC public key..."wide

Condition

uint16( 0 ) == 0x5A4D and filesize < 150KB and all of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 150KB (a cheap guard that skips large files).
  • All 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: efd87a17-7c99-404a-8ea6-2f5c2121f9f2

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE