YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_Ransom_Ragnarlocker_July_2020_1

Detects Ragnarlocker by strings (July 2020)

MalwareRagnarlockerSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X

Author: Arkbird_SOLG
Date: 2020-07-30
Modified: 2023-12-05
Score / Quality: 75 / 83

What this rule detects

Detects Ragnarlocker by strings (July 2020)

Associated malware family: Ragnarlocker.

Targets: Windows PE.

It defines 21 patterns (21 text, 0 hex, 0 regex). YARA modules used: pe.

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

Includes the imports needed to compile it on its own.

mal-ransom-ragnarlocker-july-2020-1.yarDetection Rule License 1.1

import "pe"

rule SIGNATURE_BASE_MAL_Ransom_Ragnarlocker_July_2020_1 : FILE
{
	meta:
		description = "Detects Ragnarlocker by strings (July 2020)"
		author = "Arkbird_SOLG"
		id = "60e09057-d9f8-5e89-8f47-c5dda32806c6"
		date = "2020-07-30"
		modified = "2023-12-05"
		reference = "https://twitter.com/JAMESWT_MHT/status/1288797666688851969"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/crime_ransom_ragna_locker.yar#L38-L70"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "04c9cc0d1577d5ee54a4e2d4dd12f17011d13703cdd0e6efd46718d14fd9aa87"
		logic_hash = "dc44da2f9023e0702afa8081e85ba817ebfde15f449261fae9de729d51262b04"
		score = 75
		quality = 83
		tags = "FILE"

	strings:
		$f1 = "bootfont.bin" fullword wide
		$f2 = "bootmgr.efi" fullword wide
		$f3 = "bootsect.bak" fullword wide
		$r1 = "$!.txt" fullword wide
		$r2 = "---BEGIN KEY R_R---" fullword ascii
		$r3 = "!$R4GN4R_" wide
		$r4 = "RAGNRPW" fullword ascii
		$r5 = "---END KEY R_R---" fullword ascii
		$a1 = "+RhRR!-uD8'O&Wjq1_P#Rw<9Oy?n^qSP6N{BngxNK!:TG*}\\|W]o?/]H*8z;26X0" fullword ascii
		$a2 = "\\\\.\\PHYSICALDRIVE%d" fullword wide
		$a3 = "WinSta0\\Default" fullword wide
		$a4 = "%s-%s-%s-%s-%s" fullword wide
		$a5 = "SOFTWARE\\Microsoft\\Cryptography" fullword wide
		$c1 = "-backup" fullword wide
		$c2 = "-force" fullword wide
		$c3 = "-vmback" fullword wide
		$c4 = "-list" fullword wide
		$s1 = ".ragn@r_" wide
		$s2 = "\\notepad.exe" wide
		$s3 = "Opera Software" fullword wide
		$s4 = "Tor browser" fullword wide

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 30KB and ( pe.imphash ( ) == "2c2aab89a4cba444cf2729e2ed61ed4f" and ( ( 2 of ( $f* ) ) and ( 3 of ( $r* ) ) and ( 4 of ( $a* ) ) and ( 2 of ( $c* ) ) and ( 2 of ( $s* ) ) ) )
}

Strings (21 patterns)

Identifier	Type	Value	Modifiers
$f1	text	"bootfont.bin"	fullword wide
$f2	text	"bootmgr.efi"	fullword wide
$f3	text	"bootsect.bak"	fullword wide
$r1	text	"$!.txt"	fullword wide
$r2	text	"---BEGIN KEY R_R---"	fullword ascii
$r3	text	"!$R4GN4R_"	wide
$r4	text	"RAGNRPW"	fullword ascii
$r5	text	"---END KEY R_R---"	fullword ascii
$a1	text	"+RhRR!-uD8'O&Wjq1_P#Rw<9Oy?n^qSP6N{BngxNK!:TG}\\\|W]o?/]H8z;26X0"	fullword ascii
$a2	text	"\\\\.\\PHYSICALDRIVE%d"	fullword wide
$a3	text	"WinSta0\\Default"	fullword wide
$a4	text	"%s-%s-%s-%s-%s"	fullword wide
$a5	text	"SOFTWARE\\Microsoft\\Cryptography"	fullword wide
$c1	text	"-backup"	fullword wide
$c2	text	"-force"	fullword wide
$c3	text	"-vmback"	fullword wide
$c4	text	"-list"	fullword wide
$s1	text	".ragn@r_"	wide
$s2	text	"\\notepad.exe"	wide
$s3	text	"Opera Software"	fullword wide
$s4	text	"Tor browser"	fullword wide

Condition

uint16( 0 ) == 0x5a4d and filesize < 30KB and ( pe.imphash ( ) == "2c2aab89a4cba444cf2729e2ed61ed4f" and ( ( 2 of ( $f* ) ) and ( 3 of ( $r* ) ) and ( 4 of ( $a* ) ) and ( 2 of ( $c* ) ) and ( 2 of ( $s* ) ) ) )

In plain words (Heuristic)

The file must start with “MZ” — a Windows executable (PE).
The file must be smaller than 30KB (a cheap guard that skips large files).
At least 2 patterns in ( $f* ) must match.
At least 3 patterns in ( $r* ) must match.
At least 4 patterns in ( $a* ) must match.
At least 2 patterns in ( $c* ) must match.
At least 2 patterns in ( $s* ) must match.
Uses the pe module.
Checks the PE import hash (imphash).

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References

https://twitter.com/JAMESWT_MHT/status/1288797666688851969

Sample hashes

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

04c9cc0d1577d5ee54a4e2d4dd12f17011d13703cdd0e6efd46718d14fd9aa87

Licence & attribution

Author: Arkbird_SOLG

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

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: 60e09057-d9f8-5e89-8f47-c5dda32806c6

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